Thursday, June 14, 2012
Wednesday, April 25, 2012
Study Notes Unit 2 Cell processes and Application
Protein Synthesis
1) Demonstrate a knowledge f the basic steps of protein synthesis, identifying the roles of DNA, mRNA, tRNA, and ribosome in the processes of transcription and translation.
Photosynthesis transforms solar energy into the chemical energy of a carbohydrate, it is important to a cell because the key proteins are enzymes which catalyze al reaction in cells.
The first process in photosynthesis is Transcription
-the first step in transcription is the unwinding and unzipping of the DNA helicase. the DNA controls the cell functions by controlling enzyme production.
- the second step is the matching of RNA nucleotides to DNA template. the RNA polymerase is in charge of the initiation of transcription, elongation, and also the termination of transcription.
- After matching up with the DNA, the new strand is the mRNA which leaves the nucleus to the ribosome. the mRNA is in charge of carrying coding information to the ribosome.
The second process in photosynthesis Translation. This occurs in the ribosome either attached to the ER or free floating in the cytoplasm, here a protein is produced.
- the first step in translation is the m RNA attaching to ribosome
- next step the tRNA (transfer RNA) which carries the anti-codon complimentary to the mRNA code. the tRNA carries an amino acid on its stem and a 3 nucleotide sequence.
- the third step is a peptide bond forms b/w the amino acids.
-next the ribosome moves along the mRNA, the ribosome's function is to build proteins known as polypeptides.
2) Determine the sequences of amino acids coded for by a specific DNA sequence, given a table of mRNA codons.
mRNA codons: UGG AAA GAU UUC
tRNA codons: ACC UUU CUA AAG
amino acids: TRP LYS ASP PHE
3) Give examples of 2 environmental mutagens that can cause mutation in humans.
2 environmental mutagens that can cause mutation in humans are radiation and organic chemicals.
4) Give examples to explain how mutation in DNA affect protein synthesis and may lead to genetic disorders.
An example of how mutations in DNA can affect protein synthesis and may lead to genetic disorders is Frameshit Mutations. This is when one or more nucleotides is either inserted or deleted from DNA. If this occurs the product will not make sense which results in genetic disorders.
Another example is Point Mutations this is when a change in a single nucleotide occurs and a change in a specific codon. There could be a Silent Mutation where a single codon changes but ends up being a different codon for the product needed. There could also be a Nonsense Mutation. These can lead to genetic mutations.
Transport Across Cell Membrane
1) Apply knowledge of organic molecules to explain the structure and function of the fluid mosaic membrane model.
Fluid-mosaic model of a membrane structure is the structure formed when proteins form a pattern within a bilayer of lipid molecules having a fluid consistency.
Lipids
Phospholipids make up the bilayer which are lipids with glycerol, 2 fatty acids, and a polar phosphate group described as the head. The head is hydrophilic which has water regions inside and outside the cell. The tails are hydrophobic which face each other.
Glycolipids are found on the exterior of the cell. The head is hydrophilic consisting of a straight or branching carbohydrate chain. Glycolipids make cell-cell recognition possible.
Cholesterol is a steroid lipid with a characteristic backbone of four fused carbon rings, functions to reduce the permeability of the membrane to most biological molecules.
Proteins characterize the cell, vary according to a particular membrane and time.
Channel Proteins allow particular molecules or ions to cross the plasma membrane freely
Carrier Proteins combine/ interact with specific molecules or ions so that it can cross the membrane. Carrier proteins is involved in facilitated and active transport.
Receptor Proteins shaped in a way that specific molecules can bind to it. Once it binds to a molecule, it can change its shape to bring about an intracellular response.
Enzymatic Proteins catalyzes a specific reaction.
Cell Recognition Proteins has a specific carbohydrate chain attached.
2) Explain why the cell membrane is described as "selectively permeable."
The ways of crossing a plasma membrane are classified as passive or active. Passive transport does not use chemical energy, it involves diffusion or facilitated transport. Diffusion occurs without benefit of a carrier protein where as facilitated transport does require a carrier protein.
Active transport not only requires a carrier protein but it also requires chemical energy ex ATP
All in all, certain substances can move freely whereas some need to be transported across by carrier proteins.
3) Compare and Contrast the following: diffusion, facilitated transport, osmosis, and active transport.
Diffusion is the movement of molecules from a higher to lower concentration. it does not require cellular energy.
Osmosis is diffusion specific to movement of water molecules.
Facilitated Transport is using carrier proteins and diffusion (higher --> lower concentration) and does not require cellular energy.
Active Transport movement of ions/molecules from lower to higher concentration requires cellular energy as well as carrier proteins. Transports sodium, potassium, and iodine.
4) Explain factors that affect the rate of diffusion across a cell membrane.
Factors that affect the rate of diffusion across a cell membrane are :
Size of molecule: smaller molecules diffuse more quickly than larger molecules.
Temperature: higher temperature increases rate of diffusion.
Concentration Gradient: a greater difference in concentration gradient causes faster diffusion.
Number of protein pores/carriers within the cell membrane: more pores= faster diffusion.
5) Describe endocytosis, including phagocytosis and pinocytosis, and contrast exocytosis.
Endocytosis cells take in substances by vesicle formation. Portion of plasma membrane invaginates to envelope the substance, and then the membrane pinches off to form an intracellular vesicle. Occurs in 3 ways.
1) Phagocytosis when material taken in by endocytosis is big (ex. food particles) called phagocytosis. Common in unicellular organisms such as amoebas. Occurs in humans. When endocytic vesicle fuses with a lysosome, digestion occurs. This process is a necessary and preliminary step toward development of immunity for bacterial diseases.
2) Pinocytosis occurs when vesicles form around a liquid or around very small particles. Plant root cells, cells that line the kidney tubules or the intestinal wall, and blood cells us pinocytosis. Electron microscope must be used to observe pinocytic vesicles. Involves a significant amount of the plasma membrane since it occurs continuously. Loss of plasma membrane due to pinocytosis is balanced by the occurrence of exocytosis.
Exocytosis is the outpocketing of the cell where endocytosis is the impocketing of the cell.
6) Predict the effects of hypertonic, isotonic, and hypotonic environments on animal cells.
Hypertonic solutions have more solute and due to diffusion, cell loses water to the solution which causes the cell to shrink.
Hypotonic solutions have less solute, the water goes into the cell (osmosis) the cell would expand and may burst.
Isotonic solutions have equal amounts of solute inside and outside the cell. There is no movement which results in no effect on the cell.
Enzymes
1) Demonstrate an understanding of the following terms: metabolism, enzymes, substrate, coenzymes, activation energy.
Metabolism: all of the chemical changes that occur within a cell.
Enzymes: Organic catalyst, usually a protein that speeds up a reaction in cells due to its particular shape.
Substrate: a reactant in a reaction controlled by an enzyme.
Coenzyme: a non-protein organic molecule that helps the action of the enzyme to which it is loosely bound.
Activation energy: energy that must be added to cause molecules to react with another.
2) Identify the source gland of thyroxin and relate the function of thyroxin to metabolism.
The source gland for thyroxin is the thyroid gland and thyroxin helps increase the metabolic rate.
3) Explain lock and key model of enzymatic action.
The active site of an enzyme fits with a substrate like a lock and key. The enzyme acts like the key and the substrate acts like the lock. The active site slightly adjust its shape to fit the substance perfectly.
4) Identify the role of vitamins in biochemical reactions.
Vitamins are molecules which are needed in order to trace amounts in our diet for the synthesis of coenzymes that affect health and physical fitness.
5) Differentiate between the role of enzymes and coenzymes in biochemical reactions.
Enzymes function as an organic catalyst to speed a chemical reaction, whereas coenzymes function as to help the enzyme in speeding a chemical reaction.
6) Apply knowledge of proteins to explain the effects on enzyme activity of pH, temperature, substrate concentration, enzyme concentration, competitive inhibitors and heavy metals.
pH level can alter the ionization of the r side chains and mess up the normal interaction if changed. Denaturing will occur under major pH.
If temperature is increased there will be an increase in enzyme activity because there are better effective collision b/w substrate and enzyme.
The substrate concentration if increased will increase the rate of products formed. The increase will continue until active sites of the enzyme are saturated.
If enzyme concentration increased, it can increase rate of produce formed. The concentration increases when genes are turned on and protein production occurs. The concentration decreases when genes are turned off and protein production doesn't occur.
Competitive inhibitors are molecules which are so close in shape to an enzymes substrate that it can compete with true substrate for enzymes active site.
Heavy metals decrease the amounts of active sites available.
1) Demonstrate a knowledge f the basic steps of protein synthesis, identifying the roles of DNA, mRNA, tRNA, and ribosome in the processes of transcription and translation.
Photosynthesis transforms solar energy into the chemical energy of a carbohydrate, it is important to a cell because the key proteins are enzymes which catalyze al reaction in cells.
The first process in photosynthesis is Transcription
-the first step in transcription is the unwinding and unzipping of the DNA helicase. the DNA controls the cell functions by controlling enzyme production.
- the second step is the matching of RNA nucleotides to DNA template. the RNA polymerase is in charge of the initiation of transcription, elongation, and also the termination of transcription.
- After matching up with the DNA, the new strand is the mRNA which leaves the nucleus to the ribosome. the mRNA is in charge of carrying coding information to the ribosome.
The second process in photosynthesis Translation. This occurs in the ribosome either attached to the ER or free floating in the cytoplasm, here a protein is produced.
- the first step in translation is the m RNA attaching to ribosome
- next step the tRNA (transfer RNA) which carries the anti-codon complimentary to the mRNA code. the tRNA carries an amino acid on its stem and a 3 nucleotide sequence.
- the third step is a peptide bond forms b/w the amino acids.
-next the ribosome moves along the mRNA, the ribosome's function is to build proteins known as polypeptides.
2) Determine the sequences of amino acids coded for by a specific DNA sequence, given a table of mRNA codons.
mRNA codons: UGG AAA GAU UUC
tRNA codons: ACC UUU CUA AAG
amino acids: TRP LYS ASP PHE
3) Give examples of 2 environmental mutagens that can cause mutation in humans.
2 environmental mutagens that can cause mutation in humans are radiation and organic chemicals.
4) Give examples to explain how mutation in DNA affect protein synthesis and may lead to genetic disorders.
An example of how mutations in DNA can affect protein synthesis and may lead to genetic disorders is Frameshit Mutations. This is when one or more nucleotides is either inserted or deleted from DNA. If this occurs the product will not make sense which results in genetic disorders.
Another example is Point Mutations this is when a change in a single nucleotide occurs and a change in a specific codon. There could be a Silent Mutation where a single codon changes but ends up being a different codon for the product needed. There could also be a Nonsense Mutation. These can lead to genetic mutations.
Transport Across Cell Membrane
1) Apply knowledge of organic molecules to explain the structure and function of the fluid mosaic membrane model.
Fluid-mosaic model of a membrane structure is the structure formed when proteins form a pattern within a bilayer of lipid molecules having a fluid consistency.
Lipids
Phospholipids make up the bilayer which are lipids with glycerol, 2 fatty acids, and a polar phosphate group described as the head. The head is hydrophilic which has water regions inside and outside the cell. The tails are hydrophobic which face each other.
Glycolipids are found on the exterior of the cell. The head is hydrophilic consisting of a straight or branching carbohydrate chain. Glycolipids make cell-cell recognition possible.
Cholesterol is a steroid lipid with a characteristic backbone of four fused carbon rings, functions to reduce the permeability of the membrane to most biological molecules.
Proteins characterize the cell, vary according to a particular membrane and time.
Channel Proteins allow particular molecules or ions to cross the plasma membrane freely
Carrier Proteins combine/ interact with specific molecules or ions so that it can cross the membrane. Carrier proteins is involved in facilitated and active transport.
Receptor Proteins shaped in a way that specific molecules can bind to it. Once it binds to a molecule, it can change its shape to bring about an intracellular response.
Enzymatic Proteins catalyzes a specific reaction.
Cell Recognition Proteins has a specific carbohydrate chain attached.
2) Explain why the cell membrane is described as "selectively permeable."
The ways of crossing a plasma membrane are classified as passive or active. Passive transport does not use chemical energy, it involves diffusion or facilitated transport. Diffusion occurs without benefit of a carrier protein where as facilitated transport does require a carrier protein.
Active transport not only requires a carrier protein but it also requires chemical energy ex ATP
All in all, certain substances can move freely whereas some need to be transported across by carrier proteins.
3) Compare and Contrast the following: diffusion, facilitated transport, osmosis, and active transport.
Diffusion is the movement of molecules from a higher to lower concentration. it does not require cellular energy.
Osmosis is diffusion specific to movement of water molecules.
Facilitated Transport is using carrier proteins and diffusion (higher --> lower concentration) and does not require cellular energy.
Active Transport movement of ions/molecules from lower to higher concentration requires cellular energy as well as carrier proteins. Transports sodium, potassium, and iodine.
4) Explain factors that affect the rate of diffusion across a cell membrane.
Factors that affect the rate of diffusion across a cell membrane are :
Size of molecule: smaller molecules diffuse more quickly than larger molecules.
Temperature: higher temperature increases rate of diffusion.
Concentration Gradient: a greater difference in concentration gradient causes faster diffusion.
Number of protein pores/carriers within the cell membrane: more pores= faster diffusion.
5) Describe endocytosis, including phagocytosis and pinocytosis, and contrast exocytosis.
Endocytosis cells take in substances by vesicle formation. Portion of plasma membrane invaginates to envelope the substance, and then the membrane pinches off to form an intracellular vesicle. Occurs in 3 ways.
1) Phagocytosis when material taken in by endocytosis is big (ex. food particles) called phagocytosis. Common in unicellular organisms such as amoebas. Occurs in humans. When endocytic vesicle fuses with a lysosome, digestion occurs. This process is a necessary and preliminary step toward development of immunity for bacterial diseases.
2) Pinocytosis occurs when vesicles form around a liquid or around very small particles. Plant root cells, cells that line the kidney tubules or the intestinal wall, and blood cells us pinocytosis. Electron microscope must be used to observe pinocytic vesicles. Involves a significant amount of the plasma membrane since it occurs continuously. Loss of plasma membrane due to pinocytosis is balanced by the occurrence of exocytosis.
Exocytosis is the outpocketing of the cell where endocytosis is the impocketing of the cell.
6) Predict the effects of hypertonic, isotonic, and hypotonic environments on animal cells.
Hypertonic solutions have more solute and due to diffusion, cell loses water to the solution which causes the cell to shrink.
Hypotonic solutions have less solute, the water goes into the cell (osmosis) the cell would expand and may burst.
Isotonic solutions have equal amounts of solute inside and outside the cell. There is no movement which results in no effect on the cell.
Enzymes
1) Demonstrate an understanding of the following terms: metabolism, enzymes, substrate, coenzymes, activation energy.
Metabolism: all of the chemical changes that occur within a cell.
Enzymes: Organic catalyst, usually a protein that speeds up a reaction in cells due to its particular shape.
Substrate: a reactant in a reaction controlled by an enzyme.
Coenzyme: a non-protein organic molecule that helps the action of the enzyme to which it is loosely bound.
Activation energy: energy that must be added to cause molecules to react with another.
2) Identify the source gland of thyroxin and relate the function of thyroxin to metabolism.
The source gland for thyroxin is the thyroid gland and thyroxin helps increase the metabolic rate.
3) Explain lock and key model of enzymatic action.
The active site of an enzyme fits with a substrate like a lock and key. The enzyme acts like the key and the substrate acts like the lock. The active site slightly adjust its shape to fit the substance perfectly.
4) Identify the role of vitamins in biochemical reactions.
Vitamins are molecules which are needed in order to trace amounts in our diet for the synthesis of coenzymes that affect health and physical fitness.
5) Differentiate between the role of enzymes and coenzymes in biochemical reactions.
Enzymes function as an organic catalyst to speed a chemical reaction, whereas coenzymes function as to help the enzyme in speeding a chemical reaction.
6) Apply knowledge of proteins to explain the effects on enzyme activity of pH, temperature, substrate concentration, enzyme concentration, competitive inhibitors and heavy metals.
pH level can alter the ionization of the r side chains and mess up the normal interaction if changed. Denaturing will occur under major pH.
If temperature is increased there will be an increase in enzyme activity because there are better effective collision b/w substrate and enzyme.
The substrate concentration if increased will increase the rate of products formed. The increase will continue until active sites of the enzyme are saturated.
If enzyme concentration increased, it can increase rate of produce formed. The concentration increases when genes are turned on and protein production occurs. The concentration decreases when genes are turned off and protein production doesn't occur.
Competitive inhibitors are molecules which are so close in shape to an enzymes substrate that it can compete with true substrate for enzymes active site.
Heavy metals decrease the amounts of active sites available.
Tuesday, April 24, 2012
Cell membrane
The glycoproteins and the glycolipids help stabilize the membrane structure as they form hydrogen bonds with water molecules in the fluid surrounding the cell. They act as receptors and help cell identification, hormone responses, and neurotransmission.
Glcyoproteins are also known as channel proteins, carrier proteins, receptor proteins, and enzymatic proteins. Channel proteins allow a particular molecule or ion to cross the plasma membrane freely. Carrier proteins selectively interacts with a specific molecule or ion so that it can cross the plasma membrane. receptor proteins are shaped in a way that a specific molecule can bind to it. Enzymatic protein catalyzes a specific reaction.
The cholesterol stiffens and strengthens the membrane, thereby helping to regulate its fluidity.
The carbohydrates protect the cell surfaces, it facilitates adhesion between cells, reception of signal molecules, and cell-cell recognition.
Marks reflection
I am receiving the mark I have because I have a lot of assignments due and also have to finish my posts on my blogs in order to be marked. I am going to finish my posts on my blog this week so I can get those marked and my mark can be re-evaluated. I also I have some missing labs which I shall complete and hand in sometime next week. I am going to work on my labs during my spares and finish my blog posts at home and finish those completely rather than doing half of them. Also after completing the study notes for the second unit, I am going to post the first unit study notes sometime in the upcoming next week as well.
Friday, March 2, 2012
Monday, February 27, 2012
LABELLED CELL
1) Nucleolus- dark-staining, spherical body in the nucleus that produces ribosomal subunits
2) Nuclear Envelope- double membrane that surrounds the nucleus and is continuous with the endoplasmic reticulum.
3) Ribosomes- RNA and protein in two subunits; site of protein synthesis in the cytoplasm, produces proteins
4) Vesicle-small, membrane-bound sac that stores substances within a cell
5) Rough Endoplasmic Reticulum-
6) Golgi Apparatus- organelle, consisting of flattened saccules and also vesicles, that processes, packages, and distributes molecules about or from the cell.
7) Cytoskeleton- internal framework of the cell, consisting of micro tubules, actin filaments, and intermediate filaments
8) Smooth Endoplasmic Reticulum
9) Mitochondrion- membrane-bounded organelle in which ATP molecules are produced during the process of cellular respriation
10) Vacuole- membrane-bounded sac that holds fluid and a variety of other substances
11) Cytoplasm- contents of a cell between the nucleus and the plasma membrane that contains the organelles
12) Lysosome- membrane-bounded vesicle that contains hydrolytic enzymes for digesting macromolecules
13) Centriole- cell organelle, existing in pairs, that occurs in the centrosome and may help organize a mitotic spindle for chromosome movement during animal cell division
Tuesday, February 21, 2012
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