BIO 12 UNIT 4: Study Notes

RESPIRATORY SYSTEM PARTS FUNCTIONS

1. Larynx: aka the voice box, vocal chords
2. Trachea: aka the windpipe, tube that carries air towards the lungs and out of the body, C shaped rings strengthen the trachea
3. Bronchi: Tubes divergent from the trachea that lead to the left and right lung, go to each lung
4. Bronchioles: further divisions of bronchi, lead to the alveoli 
5. Alveoli: Hollow cavities found within alveolar sacs, very thin walls allow for gas exchange between CO2 and O2 (exchange between lungs and blood), capillaries are prominent with alveoli allowing for these gases to pass (approx. 3 million alveoli in human lung)
6. Diaphragm: Contracts to aid with inhalation (increases thoracic cavity) or relaxes during exhalation
7. Ribs: Protects lungs, moves up and out during inhalation (increases thoracic cavity), opposite during exhalation
8. Pleural Membranes: Membrane that encloses the lungs, outer pleural membrane sticks to ribs and diaphragm; inner membrane sticks to lungs, allows lungs to move freely without friction, helps lungs inflate (expand)
9. Thoracic Cavity: Contains respiratory organs, "lung cavity", size and pressure effects whether inhalation or exhalation occurs

BIO 12 UNIT 4: Study Notes

VEINS AND ARTERIES FUNCTIONS

1. Subclavian Arteries-- Transports O2ated blood from the aorta to the arms
2. Subclavian Veins-- Transports deO2ated blood from the arms to the heart (RA)
3. Jugular Veins-- Transports deO2ated blood from the head to the Superior Vena Cava
4. Cartoid Arteries-- Transports O2ated from aorta to the head
5. Anterior (Superior) Vena Cava-- Transports deO2ated blood from the jugular vein to the heart (RA) 
6. Posterior (Inferior) Vena Cava-- Transports deO2ated blood from the legs to the heart (RA)
7. Pulmonary Veins-- Transports O2ated blood from the lungs to the heart (LA)
8. Pulmonary Arteries-- Transports deO2ated blood from the heart (RA) to the lungs
9. Hepatic Vein-- Transports deO2ated blood from the liver to the Inferior Vena Cava
10. Hepatic Portal Vein-- Transports deO2ated blood from the intestines to the liver
11. Renal Arteries-- Transports O2ated blood from the aorta to the kidneys
12. Renal Veins-- Transports deO2ated blood from the kidneys to the Inferior Vena Cava 
13. Iliac Arteries-- Transports O2ated blood from the aorta to the legs
14. Iliac Veins-- Transports deO2ated blood from the legs to the Inferior Vena Cava
15. Aorta-- Transports O2ated blood from the heart to the rest of the body
16. Coronary Arteries-- Transports O2ated blood from the aorta to the heart
17. Coronary Veins-- Transports deO2ated blood from the heart muscles to the heart chambers
18. Mesenteric Arteries-- Transports O2ated blood from the aorta to the intestines 

BIO 12 UNIT 4: Study Notes

1. Inferior (Posterior) Vena Cava 
2. Right Ventricle
3. Right Atrium
4. Superior (Anterior) Vena Cava 
5. Aota 
6. Pulmonary Artery
7. Left Atrium
8. Pulmonary Veins
9. Left Ventricle 

BIO 12 UNIT 4: Study Notes

KEY STRUCTURES OF THE CIRCULATORY SYSTEM

BLACK: Systematic Circulation

BLUE: Pulmonary Circulation

• Left Atrium: Sends oxygenated blood to the left ventricle via the AV valve (bicuspid/mitral)
• Right Atrium: Sends deoxygenated blood to the right ventricle via the AV valve (tricuspid)
• Left Ventricle: Sends oxygenated blood via the aortic semi-lunar valve to the aorta which in turn distributes blood throughout the body
• Right Ventricle: Sends deoxygenated blood via the pulmonary semi-lunar valve to the pulmonary trunk to the pulmonary arteries--> lungs (gas exchange)
• Coronary Arteries and Veins: Part of systematic circuit that are the initial branches off the aorta. Cardiac veins empty into the right atrium (capillary beds (exterior)--> venules--> veins)
• Anterior (Superior) Vena Cava: Sends deoxygenated blood from the upper body (head, chest and arms) to the heart (right atrium)
• Posterior (Inferior) Vena Cava: Sends deoxygenated blood from the lower body (liver, kidneys, intetsines, feet, etc.) to the heart (right atrium)
• Aorta: Sends oxygenated blood throughout the body (organs, tissues, etc.); starts near left ventricle 
• Pulmonary Arteries: Sends deoxygenated blood from the heart to the lungs for gas exchange (stems from pulmonary trunk that stems from the right ventricle)
• Pulmonary Veins: Sends oxygenated blood to the heart (left atrium) from the lungs 
• Pulmonary Trunk: Stems from right ventricle and carries deoxygenated blood from the heart to the pulmonary arteries that carry it the lungs
• Atrioventricular Valves: Located in between the atrium and ventricle for each side of the heart, allows blood into the ventricle and prevents backflow of blood back into the atria
• RA/RV= Tricuspid AV valve
• LA/LV= Bicuspid/Mitral AV valve
• Chordae Tendineae: Strong fibrous strings that prevent invertion of AV valves (blood goes to wrong chambers)
• Semi-Lunar Valves: Half-moon shaped structures located in between the ventricle and corresponding vessel; prevents backflow of blood back into the ventricle
• Pulmonary: In between the RV and the pulmonary trunk
• Aortic: In between LV and the aorta
• Septum: Separates left from right side of the heart, composed of muscular tissue 

BIO 12 UNIT 4: Study Notes

CO2 & H2 IONS AND MEDULLA OBLONGATA STIMULATION

• Increasing concentrations of carbon dioxide and hydrogen ions is detected by the respiration control centre at the brain (medulla oblongata) which in turn will INCREASE the rate of breathing 

BIO 12 UNIT 4: Study Notes

INHALATION AND EXHALATION & BREATHING INTERACTIONS

• INHALATION: Entrance of air into the lungs
• Active
• Controlled by medulla oblongata in the brain--> sends nerve impulses to the diaphragm and ribs
• Lungs expand (inflate)
• Pleural membranes stretch (allows lungs to freely expand)
• Intercostal rib muscles contract to move ribs up and out
• Ribs move up and out increasing thoracic cavity size and decreasing pressure (lower than atmospheric [air] pressure: high (in external air) to low (in body lungs))--> air enters body
• Diaphragm contracts to increase thoracic cavity size and decrease pressure 
• Thoracic Cavity size INCREASES 
• Thoracic Cavity pressure DECREASES 
• EXHALATION: Exit of air from the lungs
• Passive
• Lungs compress (deflate)
• Pleural membranes relax (constricts lung expansion)
• Intercostal rib muscles relax to move ribs in and down
• Ribs move down and in decreasing thoracic cavity size, increases thoracic cavity pressure (higher than atmospheric [air] pressure: high (in body lungs) to low (external air))--> air leaves body
• Diaphragm relaxes to decrease thoracic cavity size and increase pressure
• Thoracic Cavity size DECREASES 
• Thoracic Cavity pressure INCREASES 

VIDEO: :)

http://www.youtube.com/watch?v=HiT621PrrO0&feature=related

BIO 12 UNIT 4: Study Notes

CILIA AND MUCUS IN RESPIRATION

• Found in trachea

• MUCUS: traps debris in the lungs (dust)

• CILIA: sweeps mucus towards the throat, out of trachea

BIO 12 UNIT 4: Study Notes

FORMED ELEMENTS

1. RED BLOOD CELLS:
1. aka Erythrocytes (red-purple biconcave desks, no nuclei)
2. Come from red bone marrow
3. Transports O2 and CO2
4. Hemoglobin (red part) allows it to acquire O2 (lungs) and release it (tissues)
2. WHITE BLOOD CELLS:
1. aka Leukocytes 
2. Larger, have nucleus, translucent 
3. Come from red bone marrow
4. Fights infection
1. Neutrophils (55 to 70%): spherical, multiple lobed nuclei, granular, PHAGOCYTIC 
2. Lymphocyes (20 to 30%): spherical, one large nucleus, non-granular, SPECIFIC IMMUNITY (releases antibodies)  
3. PLATELETS: 
1. aka Thrombocytes 
2. Disk shaped, no nuclei, granular (granules in cytoplasm)
3. Aid in blood clotting

BIO 12 UNIT 4: Study Notes

PLASMA

Major Components:

1. Water (90-92%): maintains blood volume and transports molecules [source: absorbed from intestine]
2. Proteins (7-8%): maintains osmotic pressure and pH [source: liver]
1. Albumin (maintains blood volume and pressure)
2. Globulins (transport cholesterol); fight infection)
3. Fibrinogen (clotting)
3. Salts (>1%): metabolism; maintains osmotic blood pressure and pH [source: absorbed from intestine]
4. Gases (O2 and CO2): cellular respiration, end products of metabolism [source: lungs and tissues]
5. Nutrients (lipids, glucose, amino acids): provides food/energy for cells [source: absorbed from intestine]
6. Wastes (Urea): excretion by kidneys [source: liver]
7. Hormones, Vitamins, etc.: Aid in metabolism [source: varied]

BIO 12 UNIT 4: Study Notes

PATHWAY OF BLOOD

Aorta-->Arteries-->Arterioles-->Capillaries at major body organs and regions-->Venules-->Veins-->Inferior/Superior Vena Cava-->RA-->(via tricuspid AV valve) RV-->(via Pulmonary semi-lunar valve) Pulmonary Trunk-->Pulmonary Arteries-->Pulmonary Arterioles-->Pulmonary Capillaries (lungs)-->Pulmonary Venules-->Pulmonary Veins-->LA-->(via bicuspid/mitral AV valve) LV-->(via Aortic semi-lunar valve) Aorta

Video... Excellent and informative explanation of blood flow in heart:

http://www.youtube.com/watch?v=mH0QTWzU-xI

BIO 12 UNIT 4: Study Notes

FETAL VS ADULT CIRCULATION 

FETAL: Receives O2ated blood from the placenta and bypasses pulmonary circulation, 4 structures that adult does not have:

1. Oval Opening (Foramen Ovale): Between L and RA (flap acts as a valve), blood from the RA is shunted into the LA (does not need to go through the process of moving to the RV)
2. Arterial Duct or Ductus Arteriosus: Connection between pulmonary artery and aorta, reroutes blood away from lungs and sends it directly to the aorta
3. Umbilical Arteries and Veins: Arteries send deO2ated blood and wastes away from the heart and towards the placenta, Veins send O2ated blood and nutrients from the placenta to the fetus (heart)
4. Venous Duct or Ductus Venosus: Connection between umbilical vein and vena cava (liver), mixture of O2ated blood (umbilical vein) and deO2ated blood   (Vena Cava)

PATHWAY OF BLOOD: UMBILICAL VEIN-->VENOUS DUCT-->INFERIOR VENA CAVA-->RA-->OVAL OPENING-->LA-->LV-->AORTA


or UMBILICAL VEIN-->VENOUS DUCT-->INFERIOR VENA CAVA-->RA-->RV-->PULMONARY TRUNK/ARTERY-->ARTERIAL DUCT-->AORTA-->BODY (UMBILICAL ARTERIES-->PLACENTA)




A Great Video explaining Fetal Circulation:
http://www.youtube.com/watch?v=uwswhoKfkmM

ADULT: Has none of the fetal structures mentioned above AND has both Pulmonary and Systemic Circulation (uses lungs)

BIO 12 UNIT 4: Study Notes

PULMONARY VS SYSTEMIC CIRCULATION

PULMONARY-- Circulates blood from the heart to the lungs and from the lungs to the heart

**Right side of heart: RA-->RV-->PULMONARY TRUNK-->PULMONARY ARTERIES-->PULMONARY ARTERIOLES-->LUNGS (GAS EXCHANGE, BLOOD BECOMES O2ATED, CAPILLARIES)-->PULMONARY VENULES-->PULMONARY VEINS--> HEART (LA)

• ARTERIES (PULMONARY)- DeO2ated blood (away from heart)
• VEINS (PULMONARY)- O2ated blood (towards heart)

SYSTEMIC-- Circulates blood from the heart to the body (tissues and organs)

**Left side of heart: LA-->LV-->AORTA-->BRANCHES OF AORTA (ONE OF THE MANY PATHS)-->ORGANS AND BODY REGIONS 

• VEINS- DeO2ated blood (towards heart)
• ARTERIES- O2ated blood (away from heart)

BIO 12 UNIT 4: Study Notes

BLOOD VESSELS

1. ARTERIES: Thick walls, inside layer (endothelium), move blood away from heart and towards arterioles (O2ated) 

1. Inner Layer: Epithelial cells
2. Middle Layer: Elastic tissue and smooth muscle
3. Outer Layer: Fibrous connective tissue **Walls help with function to expand after heartbeat/maintain blood pressure**
2. ARTERIOLES: Smaller arteries, middle layer=smooth muscle, fibers of muscle contract and relax relating to blood pressure, transports O2ated blood towards capillaries (away from heart)
3. CAPILLARIES: Narrow, one-cell thick, endothelium walls, form capillary beds, regulates blood flow from the arterioles to the venules (bridge), gas exchange/nutrient exchange site--> O2 and other nutrients leaves thin capillary walls and joins tissue fluid, wastes diffuse into capillary                                     
4. VENULES: Small veins that drain capillary bed and join to form a vein, moves blood towards heart (deO2ated towards veins)   
5. VEINS: Has valves, brings deO2ated blood from capillary (venules) to the heart, valves allow for blood to flow in the right direction in the heart and prevent backflow, blood reservoirs (contain much of blood volume) 

                          

BIO 12 UNIT 4: Study Notes

SYSTOLE AND DIASTOLE PRESSURES

• SYSTOLE: Highest arterial pressure while heart is pumping (ventricles are contracting)
• 110-150 (normal for adult)--> fluctuates and differs depending on individual and activity/stress
• DIASTOLE: Lowest arterial pressure when heart is at rest (ventricles are relaxing)
• Should be 90 < (remains constant) 

The norm is 115/75 (Systolic/Diastolic)

VIDEOTIME... THE CARDIAC CYCLE: 

http://www.youtube.com/watch?v=jLTdgrhpDCg

BIO 12 UNIT 4: Study Notes

FACTORS AFFECTING BP: HYPERTENSION AND HYPOTENSION

• HYPERTENSION: High blood pressure (mild systole > 140 BUT severe systole > 180)
• Causes: Diet (fatty foods), obesity, hormone malfunction, arteries hardening, smoking, proper functioning kidneys help regulate this increase, reduction of stress, avoiding smoking, and eating healthy are factors that help regulate/counteract hypertension
• HYPOTENSION: Very low blood pressure (systole < 100)
• Causes: Weak pumping of heart (Often genetic or hereditary), kidneys regulate BP [ensure it does not get too low], ADH (increases BP), Renin (increases BP), and Aldosterone (increases BP)--> Response/regulation factors of Hypotension (counteract effects)

BIO 12 UNIT 4: Study Notes

AUTONOMIC NERVOUS SYSTEM REGULATION

• Involuntary Control of blood pressure and heart rate
• BP too low ---> Response is CONSTRICTION of arterial walls (smooth muscle)
• BP too high ---> Response is RELAXATION of arterial walls (smooth muscle)
• 2 Subdivisions of Nervous System:
• Sympathetic: Increases BP by increasing heart rate (Contraction: works when BP is too low, excitation, "fight or flight", unusual/dangerous situations)
• Parasympathetic: Decreases BP (Inhibits Sympathetic system, prevents an increase in BP, decreases heart rate, relaxes, works when BP is too high, stabilizer)

HERE IS A HELPFUL VIDEO EXPLAINING THE CONCEPT:

http://www.youtube.com/watch?v=YFYRosjcVuU

BIO 12 UNIT 4: Study Notes

SA Node, AV Node, Purkinje Fibers

• SA NODE= Found at upper portion of Right Atrium (wall), initiates the heart beat, sends out an "excitation" impulse every 0.85 sec to cause atrial contractions, keeps heartbeat regular (pacemaker)
• AV NODE= Found in base of Right Atrium (near septum), signals ventricular contraction by sending signals to the pukinje fibers
• PURKINJE FIBERS= Small and numerous, extending from two large fibers that carry the signal from the AV node through the ventricular walls, responsible for ventricular contractions occuring

VIDEO TIME... :)

http://www.youtube.com/watch?v=IR0nWe47eek

BIO 12 Fetal Pig Dissection Assignment

Observations: looks small, yellow, undeveloped, excess skin, feels moist, soft, toes are hard, smells like fermalphadide (stinky)
Female Pig indicated by flap located near the tail of the pig

DISCUSSION: It was a unique experience which I thoroughly enjoyed, it connected all of the big ideas of the course so far and was rich in learning opportunities. I was surprised by how small the pig was, how large the liver was, how delicate the pig was, how weird the stomach was, and how peculiar the brain was. What interested me was uncovering the various vital organs of the pig anatomy (ie locating the lungs, heart, gall bladder, etc.) This was a valuable learning experience because it for the first time visualized , the various body systems we have learned about this year in a central anatomy that we were face to face with (more meaningful than a textbook diagram). The pig showed the interconnectedness of the body systems (the digestive and excretory system, rectum, intestine, anus, the respiratory system and circulatory system, the heart, lungs, etc.)

BIO 12 UNIT 3: Study Notes

IMPORTANCE OF PH IN DIGESTIVE TRACT

• Enzymes will denature if they are not at the right pH
• Stomach pH must be acidic to kill bacteria (HCl) and for certain enzymes to activate such as PEPSIN from pepsinogen (pH 2) [breakdown of carbohydrates]
• Salivary Glands in the mouth must maintain a neutral pH for mechanical/chemical digestion to occur
• Small Intestine: pH variations to match specific digestive enzyme conditions (pancreas: sodium bicarbonate) [neutralizes acidic environment]

BIO 12 UNIT 3: Study Notes

Structure and Function of Digestive System Parts

• Mouth--> Beginning of digestive tract (where food first enters), site where chewing and initial breakdown occurs in order for food to pass through digestive tract
• Tongue--> Causes initial food break down by moistening food to make it easier to pass through digestive tract; taste buds send nerve impulses to the brain
• Teeth--> Chews large food particle into smaller more manageable chunks that can easily move down the digestive tract [sharp] (mechanical/physical digestion)
• Salivary Glands--> Lubricates food, produces saliva (salivary amylase); solid with millions of secretory cells, tiny ducts that collect saliva into one centralized duct which carries saliva from gland to mouth
• Pharynx--> Back of throat where food and air particles travel through to get to the throat (passageway)
• Epiglottis--> Thin flap of elastic cartilage located in throat, prevents food and drink from falling down the airway (safe digestion) [prevents choking and drink from  going to the wrong bodily system]
• Esophagus--> Located in throat close to trachea, food receptor when swallowing occurs with the aid of muscular contractions called peristalsis the food is delivered to the stomach through your esophagus; muscular tube
• Cardiac Sphincter--> Between stomach and esophagus, prevents heartburn  (does not allow food/acid to pass back up the trachea--> pushes down to stomach)
• Stomach--> Holding container food while it is mixed with various enzymes that further break down the food into a usable energy form, mucus protects stomach from its own acidic lining and enzymes that are responsible for chemical breakdown process, once contents are sufficiently dealt with they travel to the small intestine
• Pyloric Sphincter--> Between small intestine and stomach, smooth muscle, allows food [chyme] to enter the small intestine (duodenum)
• Duodenum--> The first 25 cm of small intestine where digestion of food occurs (starts at pyloric sphincter and extends towards the middle of the small intestine)
• Liver--> Processes nutrients absorbed from small intestine, secretes bile into small intestine to aid in digestion of fat, "chemical factory"; takes in all raw materials absorbed from intestine and produces various chemicals for body functionality, breaks down and secretes drugs
• Gall Bladder--> Stores and concentrates bile, releases to duodenum to aid with absorption and digestion of fats
• Pancreas--> Secretes digestive enzymes into duodenum that aid in fat, carbohydrate, and protein breakdown; makes and secretes insulin (key hormone in sugar metabolism)
• Small Intestine--> 22 foot long muscular tube, breaks down food with pancreas released enzymes and bile; peristalsis occurs here, food movement and mixture with digestive secretions from pancreas and liver; duodenum responsible for much of break down/digestion of food while the rest of the small intestine absorbs nutrients into the bloodstream; turns food semi-liquid to liquid (water, bile, mucous changes consistency --> nutrients absorb, left-over food residue liquid passes through intestine and eventually to colon)
• Appendix--> Four inch long tube that is connected off near the small and large intestine (lower right abdomen); unknown function (scientists assume that it stores good bacteria to replenish the body after diarrheal illness or that it serves no purpose at all [evolution])
• Large Intestine (Colon)--> 6 foot long muscular tube connecting small intestine to rectum, waste processing organ waste from digestion passes to the colon via peristalsis in liquid form, water is detracted and it is stored and released once or twice a day; stool is composed of food debris and advantageous bacteria, when colon is full of feces it empties contents into rectum to allow for elimination
• Rectum--> 8 inch chamber connecting the colon to the anus, receives waste from the colon and stores it until it is released (evacuation); when something enters the rectum brain sensors determine whether contents should be released or not; if so, sphincters relax and contract and if not than the sphincter contracts and the feeling is eventually subsided
• Anus--> Final element of digestive tract, 2 inch long canal composed of pelvic floor muscles and two anal sphincters, lining determines if contents are liquid, solid, or gas; sphincter muscles prevent stool from exiting at an inopportune time and pelvic floor stops stool from coming out when it should not; internal sphincter remains tight not allowing stool through (we are not aware of presence of stool) and external sphincter holds wastes inside until we go to the toilet during an urge to get rid of wastes

BIO 12 UNIT 3: Study Notes

Sequence of Events in Ovarian Cycle

1) Follicular phase: Follicle develops due to FSH released from the pituitary gland, this results in the the follicle producing estrogen and progesterone

2) Ovulation: occurs in midway of cycle (day 14), egg is released into the oviduct due to a surge in LH levels from the pituitary gland. 

3)Luteal Phase: Corpus luteum is formed from follicle remains, this produces progesterone and estrogen.If the egg is not fertilized during ovulation the corpus luteum disintegrates due to low levels of estrogen and progesterone and menstruation occurs at the end of this phase

Sequence of Events in Uterine Cycle

1) Menstrual Phase: Decreased levels of progesterone and estrogen due to break down of coprus luteum cause the endometrium to break down during days 1-5 of the cycle

2) Proliferation Phase: Endometrium rebuilds and thickens because of the developing follicle producing estrogen at the ovary. (Days 6-14)

3) Secretory Phase: Endometrium thickens and mucus is secreted, this is caused by the corpus luteum producing progesterone (Days 15-28)

http://www.youtube.com/watch?v=WGJsrGmWeKE&feature=related (video on the Menstrual Cycles)

BIO 12 UNIT 3: Study Notes

Hormone Roles In Ovarian and Uterine Cycle

1) FSH: promotes development of the follicle in the ovary

2) GNRH: causes release of FSH and LH from the pituitary gland.

3) LH: promotes development of corpus luteum in the ovary, also causes ovulation

4) Estrogen: low levels causes breakdown of endometrium, also helps to thicken uterine lining

5) Progesterone: low levels causes breakdown of endometrium, also helps to thicken uterine lining and produces mucus

BIO 12 UNIT 3: Study Notes

Positive Feedback Regulation of Oxytocin

Hormone is produced in hypothalamus and released by pituitary gland. Targets uterus and mammary glands. Increased contractions during during child birth cause more release of oxytocin which in turn causes more contractions. Increased suckling causes more oxytocin release and in turn more milk is released, more milk is available.

BIO 12 UNIT 3: Study Notes

FUNCTIONS OF ESTROGEN

• Targets uterus and causes thickening of endometrium (PROLIFERATIVE PHASE)
• Causes female puberty: 
• Body Hair: pubic, armpit, legs
• Increased body fat (curvy: hips and breasts)
• Breast development
• Causes eggs to mature
• Growth of uterus and vagina

BIO 12 UNIT 3: Study Notes

Hormonal Changes as a Result of Implantation

Placenta produces HCG hormone, this helps to maintain the corpus luteum until the placenta is able to make its own progesterone and estrogen

Estrogen and Progesterone sends signals to the pituitary gland so no more follicles are matured.

BIO 12 UNIT 3: Study Notes

PATHWAY OF SPERM

Seminiferous Tubules (production site)

Epididymis (immature sperm stored here, mature)

Vas Deferens (attached to Epididymis, moves sperm away from Scrotum, stores sperm and moves it towards abdomen)

Ejaculatory Duct (paired structures that are the union of the Vas Deferens and the Seminal Vesicle sends sperm to Urethra)

None 

Urethra (Shared tube with Vas Deferens at the base of the penis; expels urine and SEMEN (sperm based fluid) 

Penis (Tip is the opening of the Urethra where the sperm exits the male body)

AN AWESOME VIDEO ILLUSTRATING THIS CONCEPT:

http://www.youtube.com/watch?v=AsXjFRa4tUQ

BIO 12 UNIT 3: Study Notes

STRUCTURE AND FUNCTION OF THE MAIN PARTS OF THE FEMALE REPRODUCTIVE SYSTEM

• Ovaries--> Site of egg and hormone production, contains follicle and corpus luteum
• Follicle--> Contains egg, break apart during ovulation to release egg from ovary 
• Corpus Luteum--> Remains of the follicle after ovulation, produces hormones such as estrogen and progesterone 
• Oviducts (fallopian tubes)--> Propels egg towards uterus; site of fertilization, contains fimbrea structures at the end that sweep eggs into tubes and towards uterus
• Uterus--> Where implantation of fertilized egg occurs, site of embryonic development and childbirth, contains endometrium (blood vessels that become placenta or are menstruated monthly)
• Cervix--> Entrance to uterus, holds baby in uterus, dilates during childbirth
• Vagina--> Birth canal (where baby comes out of), exit for menstruation, site of penis reception
• Clitoris--> Contains erectile tissue (similar to penis), important in arousal, short shaft with sensitive tip covered by fold of skin (many nerve endings)

BIO 12 UNIT 3: Study Notes

TESTOSTERONE CONTROL

---NEGATIVE FEEDBACK (Decreases production of sex hormones if the levels of sperm and testosterone are too high) [homeostasis]---

*Main control centre: HYPOTHALAMUS (brain)

*HYPOTHALAMUS releases GnHR (gonadotropin releasing hormone) targeting the ANTERIOR PITUITARY 

* ANTERIOR PITUITARY secretes:

• LH (Lutenizing Hormone):
• Targets the testes (Interstitial Cells that produce testosterone)
• Increases Testosterone Production
• FSH (Follicle Stimulating Hormone)
• Targets testes (Seminiferous Tubules that produce sperm)
• Increases Sperm Production

**HYPOTHALAMUS KEEPS TESTOSTERONE AND REPRODUCTIVE HORMONE LEVEL IN CHECK WITH NEGATIVE FEEDBACK WITHHOLDING PRODUCTION OF KEY HORMONES WHEN NECESSARY**

BIO 12 UNIT 3: Study Notes

FUNCTIONS OF TESTOSTERONE

1.) Aids in sperm development

2.) Puberty in males (maturation into adulthood)

3.) Results in aggressive behaviour (fighting) and aids in sexual drive [last longer in bed--> longer erection/period of sexual intercourse]

4.) Secondary Sex distinguishing characteristics (identification of males vs. females)

• Deep voice 

• Adams Apple

• Muscles (gained from TESTOSTERONE)

• Height ("growth spurt")

• Hair growth (armpit, pubic, chest, facial, leg, arm, etc.)

BIO 12 UNIT 3: Study Notes

SPERM STRUCTURE

4 MAIN PARTS:

• TAIL- Back of sperm, flagellum structure that propels the sperm 
• MIDPIECE- Contains mitochondria that provide the sperm with ATP energy (functionality, motility, etc.)
• ACROSOME- Makes up majority of the front of sperm, contains special lysosome-like digestive enzymes that will digest outer layers of the egg during fertilization
• HEAD- The front of the sperm structure that contains the acrosome and haploid nucleus (DNA)

BIO 12 UNIT 3: Study Notes

FUNCTIONS OF SEMINAL FLUIDS

During ejaculation, the penis expels a fluid called semen made of sperm and fluids from the following three glands:

1. SEMINAL VESICLE: Secretes a high energy (fructose) fluid that serves as an energy source for sperm (motility)

2. PROSTATE: Secretes a milky, basic solution that neutralizes the acidic vagina and urethra); enhances sperm motility (sperm=more efficient and effective as a result)

3. COWPER'S: Secretes a mucus-like fluid that lubricates sperm and semen for intercourse 

BIO 12 UNIT 3: Study Notes

STRUCTURE AND FUNCTIONS OF PARTS OF THE MALE REPRODUCTIVE SYSTEM

• Testes--> Oval shaped organs that are located in the Scrotum, make Testosterone, site for the production of sperm, contain Seminiferous tubules
• Seminiferous Tubules--> Coiled masses of tubes that produce sperm cells (located in Testes in Scrotum)
• Interstitial Cells--> Located in Testes in Scrotum, located between tubules, Testosterone is produced here
• Epididymis--> Long, coiled tube that lies on the backside of each testicle, transports and stores testes produced sperm cells, site for sperm maturation
• Vas Deferens--> Long muscular tube that travels from the Epididymis to the Urethra, transports mature sperm to the Urethra (in preparation of ejaculation) 
• Prostate Gland--> Walnut-sized structure located below urinary Bladder and in front of rectum, contributes fluids to ejaculate (nourish sperm), urethra runs through centre of Prostate Gland 
• Cowper's Gland--> Pea-sized structures located on the sides of the Urethra below the prostate gland, produces a clear, slippery fluid that empties into the Urethra (lubricates the Urethra and neutralizes the acidic effect of urine residue)
• Seminal Vesicle--> Sac-like pouches attached to the Vas Deferens near the base of the Bladder, produces a fluid rich in sugar that helps sperm attain a source of energy that aid in their motility; the fluid makes up most of the volume of the male ejaculate
• Penis--> Organ used in sexual reproduction, three parts: the root, the shaft, and the glans (head), opening of Urethra found at tip of Penis, body is cylindrical and contains three circular chambers made of special tissue, semen expelled at tip of Penis; when Penis is erect than Urethra blocks the flow of urine allowing the exclusive flow of semen to be ejaculated during an orgasm
• Urethra--> Tube structure that carries urine from the bladder to outside the body, ejaculates semen when a male reaches an orgasm, when the Penis is erect during sexual intercourse it blocks the flow of urine and only allows semen to flow during ejaculation
• Scrotum--> Loose, pouch-like sac of skin that hangs behind and below the Penis, contains Testicles, nerves, and blood vessels, "climate regulator" for Testes (must make sure Testes are at a slightly lower than body temperature for proper sperm maturation), special muscles in the structure's walls allow for contraction and relaxation to allow it to heat up and cool down accordingly 

BIO 12 UNIT 3: Study Notes

ROLE OF MUCUS IN GASTRIC JUICE

• Protects stomach lining from acidic HCl (stomach would destroy itself if left in its own acidic environment)

BIO 12 UNIT 3: Study Notes

ROLE OF HCL IN GASTRIC JUICE

• Kills bacteria, activates pepsinogen which converts to pepsin (creates appropriate pH--. 2)

BIO 12 UNIT 3: Study Notes

ROLE OF SODIUM BICARBONATE IN PANCREATIC JUICE

• Neutralizes acidic chyme in small intestine (duodenum) [buffer], protects small intestine (changes pH to 8) 

BIO 12 UNIT 3: Study Notes

ROLE OF H2O IN DIGESTIVE JUICES

• Acts as a solvent for the whole mixture (dissolving quality)

BIO 12 UNIT 3: Study Notes

    ENZYME                                      GLANDULAR SOURCE                          DIGESTIVE REACTION  

Salivary Amylase	Salivary Glands	Hydrolysis of STARCH to MALTOSE (neutral pH)
Pancreatic Amylase	Pancreas	Hydrolysis of STARCH to MALTOSE (basic pH)
Lipase	Pancreas	Hydrolysis of LIPIDS to FATTY ACIDS and GLYCEROL (basic pH)
Maltase	Small Intestine	Hydrolysis of MALTOSE to GLUCOSE (basic pH)
Nuclease	Pancreas	Hydrolysis of NUCLEIC ACID to NUCLEOTIDES (basic pH)
Peptidase	Small Intestine	Hydrolysis of PEPTIDES to AMINO ACIDS (basic pH)
Trypsin	Pancreas	Hydrolysis of PROTEINS to PEPTIDES
Pepsin (comes from Pepsinogen)	Gastric Glands (stomach?)	Hydrolysis of PROTEINS to PEPTIDES

BIO 12 UNIT 3: Study Notes

VILLUS

• Located in small intestine, tiny finger like projections sticking out from the intestine to absorb nutrients (monomers)
• Villi contains tiny projections called microvilli (really small and hugely increase surface area of small intestine leading to more efficient and effective absorption)
• A villi is shaped like a tiny rod that contains a LACTEAL and CAPILLARIES 
• CAPILLARIES absorb monosacharides and amino acids
• LACTEALS absorb glycerides and fatty acids
• Rod shape means villi will be surrounded by nutrients as nutrients pass by them
• Efficient shape (rod) maximum use of space (full coverage of villi and microvilli for maximum absorption)
• Chyme gets fully broken down into nutrients for effective absorption (back of small intestine)

BIO 12 UNIT 3: Study Notes

SMALL INTESTINE 

• Secretes mucous (protection)
• Organs secrete products into LUMEN of small intestine (gall bladder--> bile (fat emulsification/movement in blood stream), pancreas--> bicarbonate (buffer to counteract stomach acid), pancreas--> amylase (carbohydrate break down), pancreas--> lipase (break down of fats)) 
• Specialized anatomical structure of each part of small intestine= absorbs different things at different parts (i.e. amino acids and fructose)
• Active and Passive transport of nutrients (dependent on what it is, specialized structures, etc.)
• Microvilli composition of small intestine increases surface area and rate of absorption of monomers (lacteal and capillaries)
• Epithelial cells is where absorption occurs

Here is a brief video talking about digestion and absorption in the small intestine:

http://www.youtube.com/watch?v=P1sDOJM65Bc

BIO 12 UNIT 3: Study Notes

SWALLOWING AND PERISTALSIS

SWALLOWING:

Movement of food from mouth through pharynx into esophagus and then the stomach

STEPS:

1.) A mass of chewed and moistened food (bolus) is pushed to back of mouth by tongue, in pharynx a swallowing reflex prevents food from entering lungs and directs it to the esophagus

2.) Muscle contractions in the esophagus (peristalsis) propel bolus

3.) Bolus passes through specific sphincter and goes into stomach (heartburn results from irritation of esophagus by leaking gastric juices from sphincter)

• Uvula- deflects large food particles (gag reflex)
• Soft palette- closes nasal cavity during swallowing 
• Epiglottis- closes trachea during swallowing

PERISTALSIS: 

• Rhythmic contractions of soft muscular esophagus lining, stomach and small intestine propels food through digestive tract

HERE IS A VIDEO OUTLINING THE STEPS IN DIGESTION:

http://www.youtube.com/watch?v=b20VRR9C37Q

BIO 12 UNIT 3: Study Notes

BILE AND THE EMULSIFICATION OF FATS

• Contains salts (cholesterol) which break fats up into droplets, providing larger surface area for digestive enzymes to work on (physical/mechanical digestion)

BIO 12 UNIT 3: Study Notes

LIVER

FUNCTIONS:

1.) Detoxification of blood by removal of poisonous substances (drugs)

2.) Stores iron, fat soluble vitamins A, D, E, K

3.) Makes plasma proteins from amino acids

4.) Stores glucose as glycogen after eating and breaks down glycogen to glucose to maintain glucose concentration of blood (energy) in between meals

5.) Produce urea from hydrolysis of amino acids

6.) Coverts red blood cell hemoglobin to breakdown products which have been excreted and bile salts in bile

**7.) Produces bile (stored in gallbladder before entering small intestine where salts of bile emulsify fats)

BIO 12 Week in Review...

The past week we...

• MON- Female Reproductive System Cut + Paste, /13 assignment (completed colouring and q's, labeling, cut and paste for marks in class)
• TUE- Notes on Estrogen, discussed marks, test, etc.
• THU- Notes on Testosterone (finished reproduction unit), started Circulatory System with an intro. class discussion of its functions and general knowledge, Colouring sheet, structure and functions sheet of the major parts of the circulatory system (started and completed for homework), notes on the Heart, Replication of the Movement of blood in the heart/body activity (Abstract heart created with construction paper, strings)
• FRI- Notes on Stimulation of the Heart, COOKIE DECORATING (using icing [blue and red], candy rope [blue and red], and smarties to create a heart which shows the movement of blood and its nodes--> picture can be viewed on the blog), labeling sheet of the heart and blood movement, final good-byes to Ms. Phillips (wishing her a speedy and smooth recovery, my heart goes out to you, will miss you as our BIO teacher)

BIO 12 Cookie Heart

An image of our "cookie hearts" (Above) :) 

LEGEND:

Blue side (Right atrium and Right Ventricle= deO2ated blood)
Red Side (Left Atrium and Left Ventricle= O2ated blood)
Brown Smartie (SA Node)
Yellow Smartie (AV Node)
Blue Candy (DeO2ated blood flow= Superior Vena Cava--> Right Atrium--> Pulmonary Trunk/Arteries--> Lungs)
Red Candy (O2ated blood flow= Lungs--> Left Atrium (via pulmonary arteries and veins)--> Aorta--> Body)

Digestive System Question

• Why do farts stink, why do we fart (causes), how do we fart?

A: 

1. Remnants of hydrogen sulfide (gaseous) and skatole contribute to the odour of farts [SULFUR] (ex. eating eggs produces stinky farts due to being rich in sulfur which is derived from bacterial production in guts). 

2. Ingesting too much air (eating/drinking too fast), insoluble food content, unfamiliar or abundant quantity of food causes more frequent farting which is the product of chemical digestive system processes: hydrolisis of carbohydartes and proteins in foods

3. Gases produced in the stomach and intestines from the aforementioned biochemical processes, gas travels up (burp) or down towards rectum and is expelled through anus (FART)

BIO 12 Week in Review...

This is what happened this week in biology...

• MON- Started new unit on Digestive System by watching a video and researching some of the functions of the parts of the digestive system with the use of a sheet, created poetry? with those sheets, talked about marks (work handed back)
• TUES- Continued working on functions with the I-PADS and also created a blog post reflecting on our mark so far...
• THURS- UNIT 2 TEST (pretty good... a few tricky m.c. q's and a written q or two but overall I did really well), started Digestive System T-Shirts, notes on Digestive System
• FRI- Digestive System notes continued, digestive system colouring and q's, talked about what is to come this year (Playland, Reproduction, Marks, etc.)

BIO 12 UNIT 2: Study Notes

PROTEIN SYNTHESIS

• Transcription:

• Occurs in nucleus of eukaryotic cells
• Definition:
Making a mRNA from a DNA template
• STEP 1-
DNA Helicase unzips and unwinds a double-helix DNA molecule
• STEP 2-
RNA Polymerase aids in matching RNA nucleotides to the DNA template strand (only one of the two DNA strands) [COMPLIMENTARY BASE PAIRING]
• STEP 3-
Completed mRNA strand leaves the nucleus and goes to the ribosome (also, DNA is rewound)

• Translation:

• Occurs at the ribosome of eukaryotic cells

• Definition: Production of a protein

• STEP 1- mRNA attaches to the ribosome (this is the strand from the aforementioned process of Transcription) [INITIATION]

• STEP 2- tRNA: an amino acid head and anti-codon tail that complimentary pairs to a specific codon of the mRNA strand (3 a.a. group) that results in the release of its specific amino acid head (coded for via base pairing between anti-codon and mRNA codon); only two tRNA molecules are at the ribosome releasing their amino acids at one time 

• STEP 3- Peptide bonds form between each pair of amino acids 

• STEP 4- mRNA shifting along the ribosome similar to a conveyor belt in that two tRNA arrive, release the amino acid and than move away to allow a new tRNA to come and release its amino acid head and so on this process occurs at an extremely quick pace [ELONGATION]

• STEP 5- Emptied tRNA molecules (i.e. no amino acid head) leave the ribosome after releasing an amino acid (their job is done)

• STEP 6- The completed long strand of amino acid monomers joined together to form a protein designated for a very specific role in the cell relating to a chemical reaction (enzymes); [TERMINATION] occurs which basically breaks apart the ribosome and allows the protein to exit and go where it needs to go to complete its function in the cell 




Here is a video explaining Protein Synthesis...

http://www.youtube.com/watch?v=D3fOXt4MrOM



but really who needs that when I made my very own SHOW ME video (link on blog) ;)

BIO 12 UNIT 2: Study Notes

PROTEIN SYNTHESIS

• With the help of the above mRNA genetic codon table it is easy to move from a DNA sequence of codons to the mRNA and amino acids:

AAT GCG CTT CAT TAA ATT (DNA)

UUA  CGC  GAA GUA AUU UAA (mRNA)

Leu    Arg    Glu    Val    Iso   STOP (a.a.)

BIO 12 UNIT 2: Study Notes

PROTEIN SYNTHESIS

• Environmental Mutagens [MUTATIONS]:



• Radioactive residue/decay (gamma, alpha, beta particles/rays)

• UV Rays (exposure to sunlight)




Here is a brief but effective video...



http://www.youtube.com/watch?v=0wrNxCGKCws

BIO 12 UNIT 2: Study Notes

PROTEIN SYNTHESIS

• Mutations and their effects:

• Definition: A change in the base sequence of DNA
• Causes: Radiation exposure and chemicals [Mistakes in base pairing during P.S.]
• TWO MAIN TYPES:



• Point: Single nucleotide base changes in a gene's DNA sequence

• MISSENSE- single amino acid change within the protein (ex. sickle red blood cell; body not able to make blood as effectively and many  gain fatal diseases; TGT --> TGG is Cys --> Trp)
• NONSENSE- create a premature "stop" codon creating a shortened protein (ex. TGT --> TGA is Cys --> STOP; can cause diseases as serious as Cystic Fibrosis)
• SILENT- have no effects (i.e. no change) in amino acids of a protein (ex. GUU --> GUC is Valine; no changes just different base letters but coding for the same amino acid, common in Protein Synthesis)

• Frameshift: Occurs when bases are inserted or deleted from DNA sequence, shift in reading the frames of the codons which are differed as a result 

• ADDITION- the addition of an extra amino acid or more in the DNA sequence to create altered amino acid sequence and possibly non-functional proteins (ex. Huntington's disease caused by insertion of duplicates of triplet nucleotides)
• DELETION- making the sequence shorter, missing one or more bases leading to completely different codons and a.a.'s and possibly a non-functional protein (ex. Can cause many diseases/disorders including infertility for males)




Here are good videso discussing mutations...

http://www.youtube.com/watch?v=gQrq3CuPjxs&feature=results_video&playnext=1&list=PLD3C8F40032F0B234


http://www.youtube.com/watch?v=_tvP6iJEVH0

BIO 12 UNIT 2: Study Notes

TRANSPORT ACROSS THE CELL MEMBRANE

THE FLUID MOSAIC MODEL

PROPERTIES OF MEMBRANE:

• "Phospholipids" grout and "Proteins" tiles
• Pliable (vesicles bud off and fuse)
• Phospholipid Bi-layer has a certain fluidity 
• Asymmetrical (Phospholipids vertically face opposite directions of the membrane)

 STRUCTURAL COMPONENTS:

• PHOSPHOLIPIDS: main structural component, isolates cell cytoplasm from exterior, hydrophillic (head region) faces intracellular and extracellular fluids, hydrophobic (tail region) face eachother, allows and restricts molecules from enetering/exiting the cell 
• CHOLESTEROL: lipid embedded within membrane, makes bilayer stronger, more flexible, and less fluid, hydrophobic nature restricts water soluble molecules from penetrating the membrane
• GLYCOLIPIDS: phospholipids attached with a carbohydrate (straight or branched glucose sugar chains); provide cell with a specific recognition/ID marker to help prevent against certain diseases, illnesses, etc. from recurring

PROTEINS:

TWO MAIN TYPES: 

1. Integral--> Embedded within bilayer, hydrophobic regions embedded in membrane, hydrophillic regions extending from the bilayer

2. Peripheral--> Attached to the surface of membrane, held by protein filaments or free drifting laterally [MOSAIC]

• RECEPTOR: has a distinct binding site, molecular triggers that set off cell responses w/ specific molecules in extracellular fluid [Integral]
• GLYCOPROTEINS: proteins with an attached carbohydrate chain that projects externally from the membrane; ID/recognition markers [like glycolipids], cell surface attachment sites {Peripheral}
• TRANSPORT: regulate movement of water-soluble molecules through the membrane; Channel: form pores that allow smaller water-soluble molecules to penetrate the membrane & Carrier: have binding sites, require ATP energy to help move larger molecules across the membrane [Active Transport, Endo and Exocytosis] [Integral]

BIO 12 UNIT 2: Study Notes

TRANSPORT ACROSS THE CELL MEMBRANE

SELECTIVE PERMEABILITY

WHY IS THE MEMBRANE CONSIDERED SELECTIVELY PERMEABLE?

• It can choose what exits and enters the cell (unique mechanism), it chooses what the cell needs to perform specific functions/ what is best for the cell at the time, what it needs, prevents harmful substances from entering the cell.
• EXAMPLE: If the membrane only needs Potassium than it can and will only allow Potassium in the cell (channel)

BIO 12 UNIT 2: Study Notes

TRANSPORT ACROSS THE CELL MEMBRANE

TRANSPORT TYPES

1. PASSIVE: does not need ATP energy


1. Diffusion: movement of molecules across the membrane from an area of high [ ] to low [ ] {ex. CO2 and O2 in lungs + body tissues} (between phospholipids)
2. Osmosis: movement of water molecules (diffusion of water) across the membrane from an area of high [ ] to low [ ] (water has its own carrier protein)
3. Facilitated: diffusion (high to low []) with the aid of a carrier protein {ex. Glucose sugars in small intestine}


2.  ACTIVE: uses ATP energy
1. Active: use of a transport protein that helps molecules move against the concentration gradient (low to high [ ]); needs ATP energy
2. Endocytosis and Exocytosis [described later...]   

VIDEO TIME...

• Passive transport-->  http://www.youtube.com/watch?v=JShwXBWGMyY
• Active Transport -->  http://www.youtube.com/watch?v=STzOiRqzzL4&feature=results_video&playnext=1&list=PL22852FE67A13AEC7

BIO 12 UNIT 2: Study Notes

TRANSPORT ACROSS CELL MEMBRANE

FACTORS AFFECTING THE RATE OF DIFFUSION ACROSS CELL MEMBRANE:

• Size: Smaller Molecule (size and mass)= diffuse faster  
• Temperature: Higher temperature= higher rate of diffusion
• Concentration Gradient: Greater difference in concentration gradient= faster diffusion
• Number of protein pores or carriers in cell membrane: More Pores= faster diffusion

BIO 12 UNIT 2: Study Notes

TRANSPORT ACROSS CELL MEMBRANE

ENDOCYTOSIS AND EXOCYTOSIS (ACTIVE TRANSPORT, CONT.)

• ENDOCYTOSIS: using a vesicle; infolding of membrane to form vesicles around materials, requires ATP energy, larger molecules entering/exiting cells
• Phagocytosis: cell eating, engulfment of solid material
• Pinocytosis: cell drinking, engulfment of liquids

• EXOCYTOSIS: release of vesicle contents outside of cell by fusion of vesicle and membrane [opposite process of endocytosis], ATP energy

Here is a helpful video to provide visual of the processes: 

http://www.youtube.com/watch?v=DuDmvlbpjHQ

BIO 12 UNIT 2: Study Notes

TRANSPORT ACROSS CELL MEMBRANE

HYPERTONIC, HYPOTONIC, ISOTONIC 

• HYPERTONIC
• H2O molecules move from an area of high [H2O] in the cell to a low [H2O] outside the cell {water moving out of cell}
• Results in "Crenation" (Shriveling/shrinking of cell)

• HYPOTONIC 
• H2O molecules move from an area of high [H2O] outside cell to a low [H2O] inside the cell {water moving into the cell}
• Results in "Lysis" (Swelling/bursting of cell)

• ISOTONIC
• H2O molecules at equal rates into/out of cell 
• Results in equilibrium (even amount of H2O molecules inside and outside cell)

BIO 12 UNIT 2: Study Notes

TRANSPORT ACROSS CELL MEMBRANE

SURFACE AREA: VOLUME & CELLS

--> Cells need to IMPORT nutrients and EXPORT wastes via diffusion (quickly and efficiently: best for cell= needs constant diffusion)

--> Small Cells have a HIGH surface area to volume ratio opposite for large

                        

                             SO WHY ARE CELLS SO SMALL?

• It is better to have many small cells that take up the same space as one large cell (back to being more efficient and quick in import/export)
• Surface Area is the cell membrane [import/export of wastes and nutrients]; SA to Volume ratio is smaller with one large cell so... it is unable to diffuse materials into and out of cell effectively or sometimes at all (that is why we are composed of billions of small cells)

To increase cell surface area (make a more effective cell):

• Divide (as mentioned, smaller cells that have a larger surface area to volume ratio are better!!!)
• Wavier Surfaces (Elongates/makes bigger while occupying same volume, bigger SA=better!!)
• Long and Skinny (Greater SA=better!!!, elongating to make more effective while occupying same volume as a fat cell)

                         

BIO 12 UNIT 2: Study Notes

ENZYMES

KEY TERMINOLOGY

• Metabolism: Chemical reactions that occur in cells of living organisms that are crucial to their survival
• Enzymes: Proteins whose shape determines its function, coded for by DNA, produced at ribosome during Protein Synthesis (Transcription), catalyze chemical reactions without being consumed, work to decrease activation energy
• Activation Energy: The amount of energy that must be supplied to cause molecules to react with one another [Enzyme binding sites decrease A.E.]
• Substrate: "Reactants" of the chemical reaction (the entities that  bind to active sites of apoenzymes to help create Enzyme Substrate Complex --> products)
• Coenzymes: A non-protein molecule that is beside the apoenzyme to complete the active site structure so that enzyme catalyzation can occur

BIO 12 UNIT 2: Study Notes

ENZYMES

THE LOCK AND KEY MODEL

• The Apoenzyme represents the lock and the substrates represent the key that fit perfectly in place like a specific key (exact shape and size) into the key hole (active site) of the larger lock (apoenzyme)

BIO 12 UNIT 2: Study Notes

ENZYMES

ROLE OF VITAMINS IN BIOCHEMICAL REACTIONS

• Coenzymes are large molecules that the body is incapable of synthesizing SO...
• Vitamins are ingested, only required in small quantity, to help alter this deficiency  
• EXAMPLES: niacin, thiamin (B1), etc. are examples of these vitamins that are part of co-enzymes 

BIO 12 UNIT 2: Study Notes

ENZYMES 

ENZYMES VS. COENZYMES IN BIOCHEMICAL REACTIONS

• ENZYMES: 
• Organic catalyst that speeds up the reaction
• COENZYMES:
• Help the enzyme speed up the chemical reaction 

Here is a video talking about enzymes at a basic level:

http://www.youtube.com/watch?v=V4OPO6JQLOE

BIO 12 UNIT 2: Study Notes

ENZYMES 

FACTORS AFFECTING ENZYME ACTIVITY:

1. pH: Enzymes generally survive at a 6-8 level pH, regardless if an enzyme is altered drastically in pH level (ex. stomach acids) will cause denaturation, a change in shape, and thus a change in function/makes it non-functional; in a sense if this happens than the reaction(s) involving the effected enzyme(s) cannot happen (no ES complex), in major cases large disruptions in pH and much denaturation will result in eventual death (no chemical reactions occurring in body); in less severe instances a change in pH slows r.o.r.

   2. Temperature: body temperature = 36.9 degrees Celsius; DECREASING the temperature SLOWS rate of reaction but does NOT denature proteins, INCREASING the temperature SPEEDS up the rate of reaction BUT after the temperature moves towards and beyond 45 degrees the enzyme DENATURES, changes shape, does not function properly, reactions are restricted and in serious cases, as mentioned, death may occur

3. Substrate Concentration: Higher [substrate] will increase the amount of product until optimal saturation is reached at which point a constant production continues. Often times, the [substrate] does not limit a reaction's rate/capability (i.e. unless substrate runs (highly improbable) out than [substrate] is hardly ever negative or major)

4. Enzyme Concentration: Higher [Enzyme] = higher rate of reaction, more product produced, increased enzymatic activity; Lower/decrease in [Enzyme] results in less product forming BUT production will not likely stop completely unless all substrate is not available (highly improbable) 

5. Competitive Inhibitors: Mimic the shape of the substrate and thus disrupt the reaction from happening or at least happening properly (i.e. not the right substrate needed to produce enough of what is required in the reaction) [irreversible]; ex. poisons

6. Heavy Metals: Decrease number of available active sites (decrease enzymatic activity, product formation, rate of reaction) because of denaturation (irreversible); ex. lead and mercury