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 

BIO 12 UNIT 2: Study Notes

ENZYMES

THYROID GLAND AND THYROXIN

• Source Gland of Thyroxin--> Thyroid Gland, located in neck attached to the trachea below larynx
• Thyroxin stimulates all cells of body for faster rate of metabolism (more glucose is broken down for usable ATP energy as a result)

BIO 12 Marks Overview

I am currently getting 100% and am extremely happy as such, to be achieving this result in a high standing academic course; an accomplishment to be proud of. I am interested and enthusiastic about the content and as a result expend great effort to display my exciting learning and knowledge.

As well, the way the course is being taught by my and I am honest here all time favorite high school teacher, Ms. Phillips is awesome; a variety of applications of our learning, an enthusiastic delivery, and the technological innovation (I love the ideas of the blog and electronic assignments, it is great life skills for a world revolving around technology)

Ms. Phillips deserves as much credit and more for being a great teacher who truly is spectacular.

BIO 12 Week In Review...

This Past Week...

• MON- Cell Membrane Transport Quiz (16/16! :) ), Enzyme Colouring and Q's
• TUES- Enzymes Notes (hahaha... without tables or desks) [Class Physical Demonstratin]
• THURS- Enzyme Inhibition Notes, Enzyme In-Class Lab Activity (using toothpicks in beakers= fun and educational!!), Factors Affecting Enzyme Activity Notes, "Assessment" Quiz on Enzymes (did video explaning concepts)
• FRI- We worked outside in the sunshine today!!! Did textbook questions on thyroid glands, a more difficult critical thinking experimental questions sheet was also started (highlight of the day was the wind blowing away Ms. Phillips papers... i'm sorry but LOL!!!)

UNIT 2 TEST IS ON THURSDAY!!! Coming Soon... Unit 2 Study Notes

BIO 12 Week in Review...

The Week that is now over:

• TUES- Notes on Passive and Active Transport, Colouring and Q's on Active Transport, Marks talk 
• THU- Passive Transport Colouring and Q's, discussion about Passive Transport, Osmosis, and hypertonic, hypotonic, and isotonic solutions, Cell Membrane Review Sheet, Factors Affecting Rate of Diffusion Notes, Lab on Rate of Diffusion (agar cubes)
• FRI- Time given to work on Lab Reports from previous classes and handed in, In-class Cell Membrane Review in preparation for a Quiz on Monday!!! 

• Here is an educational video link explaining Cell Membrane Transport:

http://www.youtube.com/watch?v=kfy92hdaAH0

BIO 12 Week in Review...

Looking back at the week that was...

• MON- Completed Colouring and Q's for Cell Membrane topic, did notes on the Cell Membrane and movement
• TUE- Osmosis Lab: Created a dialysis tube "bonbon" and tested to see how it acted as a "cell membrane"
• THU- Given time to complete our Osmosis Lab Assignment, completed/posted our Cell Membrane Functions assignment, and completed a Osmosis and Diffusion Lab, including the Q's and observations (some of the concepts were a little troublesome...)

A looong weekend!!!! yes!!! 

BIO 12 Cell Membrane Components Functions

Receptor Proteins- Molecular triggers that set off cell responses according to specific molecules in the extracellular fluid (above). 

BIO 12 Cell Membrane Components Functions

Transport Proteins- Regulate the movement of water-soluble molecules through the membrane. 

TWO TYPES:

1. Channel Proteins- Form pores that allow smaller, water-soluble molecules to enter/exit the membrane (Passive Transport--Door)
2. Carrier Proteins- Contain binding sites that require ATP energy to aid in the movement of molecules across the membrane (Active Transport--Endo- & Exocytosis--No size discrimination)

BIO 12 Cell Membrane Components Functions

Glycoproteins- Proteins with an attached carbohydrate chain that pops out externally from the top of the membrane. Can serve as cell surface attachment sites or ID tags (like glycolipids)

BIO 12 Cell Membrane Components Functions

Glycolipids- Phospholipids with attached carbohydrate chains. The chains of glucose provide the cell with a unique signature or self-recognition marker. 

BIO 12 Cell Membrane Components Functions

Cholesterol- Makes bi-layer stronger, more flexible, and less fluid. Hydrophobic nature makes membrane less permeable. (embedded within membrane)

BIO 12 Functions of Cell Membrane Components

Phospholipid- Main structural component of cell membrane, hydrophilic and hydrophobic areas allow and restrict molecules from entering and exiting the cell, isolates cytoplasm from external environment