Show:
Biochemistry
C.R. and P.S.
Homeostasis 1
Homeostasis 2
Genetics
100
Name the 3 macromolecules that we get from food. State their building blocks/simpler components and the type of bond that joins these building blocks together.
Carbohydrates are made up of monosaccharides (ex: glucose), which are joined by glycosidic linkages. Lipids are made up of glycerol + 3 fatty acids joined by ester linkages. Proteins are composed of amino acids joined by peptide bond.
100
How many ATP molecules are produced in each stage of cellular respiration (per 1 glucose molecule)? Explain why we write 36 ATP in the chemical equation for cellular respiration when the sum of the numbers above is not 36.
Glycolysis: 4 ATP Pyruvate oxydation: 0 ATP Krebs cycle: 2 ATP Electron Transport Chain: 32 ATP 4 + 0 + 2 + 32 = 38 ATP, but we write 36 ATP because glycolysis uses up 2 ATP molecules, which leaves a net of 36 ATP molecules.
100
You are swimming in the Mediterranean Sea and all of a sudden you see a shark. Your body releases adrenaline into the blood. State 5 physiological changes that will occur due to the adrenaline.
- increased heart rate - increased respiratory rate - increased blood sugar - pupils dilate - decreased blood flow to digestive organs - increased blood flow to muscles - blood vessels dilate - increased cell metabolism (more cellular respiration, so more ATP made)
100
Define homeostasis and give one example of it in the human body.
Homeostasis is the maintenance of a constant condition in the internal environment despite changes to the external environment. Ex: temperature control, water balance, blood glucose, ion balance, pH balance
100
Using the codon/amino acid chart from the textbook or from your notes, convert the following mRNA strand into a protein (amino acid sequence): 5` - AUGCGGUUACACGUCUGA - 3`
Met-Arg-Leu-His-Val-STOP
200
State 3 differences between triglycerides and phospholipids.
1) Phospholipids have 2 fatty acids, triglycerides have 3. 2) Phospholipids have a phosphate group, trilgycerides don't. 3) Phospholipids are partially hydrophobic and partially hydrophilic, while triglycerides are hydrophobic.
200
Name and briefly summarize/explain the 3 stages of the light reactions of photosynthesis.
1) Photoexcitation - light (photons) strike chlorophyll molecules and give energy to chlorophylls’ electrons. 2) Electron Transport - the electrons travel through a series of electron carriers in the thylakoid membrane, which creates an H+ reservoir in the thylakoid lumen. 3) Chemiosmosis - the H+ leave the thylakoid lumen through ATP synthase, and ATP synthase uses the energy stored in the H+ to make ATP.
200
Fill in the blanks. The nephron is the functional unit of the ____. The three processes that occur in the nephron are filtration, ____, and ____. Filtration takes place in the ____. Glucose leaves the nephron from the ____ tubule via ____ transport, while drugs and K+ ions enter the nephron in the ____ tubule via ____ transport.
kidneys, reabsorption, secretion, glomerulus, proximal, passive, distal, active
200
Fill in the blanks with the appropriate hormones. Ovulation in women is stimulated by ___ but can be inhibited by ___. Spermatogenesis in men can be caused by ___ and ___.
LH, progesterone. FSH/testosterone.
200
5` - AATAGCCTAGTAGC - 3`. Give the sequence for a strand of DNA that is complementary to the given one above, and a sequence for a complementary strand of RNA. If the enzyme Z has a recognition sequence of TAGA (and it cuts between the A/G), how many times could the enzyme cut this piece of DNA, and how many pieces would be formed?
3` - TTATCGGATCATCG - 5` for the complementary strand of DNA. 3` - UUAUCGGAUCAUCG - 5` for the complementary strand of RNA. The enzyme could not cut this piece of DNA because it does not have the necessary recognition sequence.
300
A group of cells in your body make an important chemical that is then released into the blood. a) Given that there is always more of that chemical outside on of these cells than inside, what type of transport would one of these cells use to release the chemical? Explain how you know. b) Name 1 thing that will be needed to transport this chemical out of the cell.
a) The cell will use active transport (exocytosis) to release the chemical, since the chemical is going against its concentration gradient (from an area of low concentration inside the cell to an area of high concentration outside the cell). b) The cell will need ATP to transport the chemical, since active transport requires energy.
300
What are the 2 ways in which ADP can be converted to ATP, and in what stage(s) of cellular respiration is each method used?
1) Substrate phosphorylation - enzyme adds an inorganic phosphate to ADP; used in glycolysis, pyruvate oxidation and in the Krebs cycle 2) Oxidative phosphorylation - a series of redox reactions in which electrons are passed along to the final acceptor (oxygen), and protons are pumped into the intermembrane space of mitochondria, which creates a concentration gradient that provides the energy for ATP synthase to produce ATP. Used in stage 4, the electron transport chain.
300
Explain the regulation of blood sugar levels.
Low blood sugar levels —> alpha cells of pancreas release glucagon —> glucagon stimulates liver to convert glycogen to glucose and release the glucose into the blood —> increased blood sugar levels. High blood sugar levels —> beta cells of pancreas release insulin —> insulin makes cells take up glucose from the blood and makes the liver convert glucose to glycogen —> decreased blood sugar levels.
300
Explain the differences between sensory neurons, interneurons, and motor neurons.
Sensory neurons - carry information from our 5 senses found in the peripheral nervous system to the CNS. Interneurons - carry information within the CNS (brain + spinal cord), link sensory and motor neurons. Motor neurons - carry messages from the CNS to effectors (muscles, glands, etc.).
300
Explain what happens in mRNA processing and why each step/process is necessary.
1) Splicing (Introns cut out, exons glued back together by spliceosome) - done because the introns don’t code for an amino acid. 2) Capping (adding a 5` guanine cap to the mRNA) - protection from enzyme digestion, also helps ribosome attach to mRNA and start translating. 3) Tailing (adding a poly A tail to 3` end of mRNA) - helps protect mRNA from enzyme digestion.
400
Which type of fat will have a higher boiling point, unsaturated fatty acids or saturated fatty acids? Explain why.
Saturated fatty acids will have a higher boiling point because they are saturated with hydrogen atoms (single bonds), resulting in long straight hydrocarbon chains. These chains are compact and can group together, which results in higher Van der Waals forces and a higher boiling point. Unsaturated fatty acids have kinks due to their double bonds, making them not as compact as saturated fatty acids. This results in lower Van der Waals forces and a lower boiling point.
400
Describe what happens in the electron transport chain (use both NADH and FADH2 when explaining).
NADH enters the ETC at NADH hydrogenase, and releases its electrons. The electrons are passed along 3 proton pumps to oxygen, the final accepter. For each electron, a proton pump will pump an H+ atom from the mitochondrial matrix into the inter membrane space. As a result, there will be a proton gradient (more H+ in the inter membrane space than in the matrix), which stores potential energy. The H+ atoms enter the matrix through ATP synthase, and the potential energy is used to make ATP. Same thing for FADH2, except that it enters the ETC later than NADH, its electrons only pass through 2 proton pumps, so 2 ATP are made per FADH2.
400
Explain depolarization, repolarization, and hyperpolarization.
Depolarization - Na channels open and Na rushes into the neurone, making it more positive on the inside; it may cause an action potential if the neuron is depolarized (from -70 mV) to -50 mV. Repolarization - occurs after an action potential; K+ channels open and K+ rushes out of the cell, making the cell more negative (decreases the cell’s membrane potential from 20 mV to -70 mV). Hyperpolarization - occurs after an action potential and repolarization, when the cell’s membrane potential drops even lower than -70 mV.
400
Explain how the kidneys are involved in regulating the pH of our bodies.
CR releases H+ ions into the blood which lowers the pH, so we have a buffer system to help raise the pH: H+ + HCO3- —> H2CO3 —> H2O + CO2. However, this reaction uses up HCO3- ions. The kidneys create more HCO3- ions by reversing this reaction in the cells of the proximal and distal tubules.
400
Explain DNA replication, making sure to include all the steps and major enzymes/proteins.
DNA helicase unwinds the double stranded DNA. DNA gyrase relieves tension caused by the unwinding. SSBPs bind to each strand of DNA and prevent them from re-coiling. RNA primes lays down RNA primers. DNA polymerase III attaches to these primers, reads the DNA template and synthesizes a daughter strand in a 5` to 3` direction (both leading and lagging strands). DNA polymerase I removes the primers and fills them in with the appropriate DNA. DNA ligase joins the Okazaki fragments on the lagging strand together. DNA polymerase I and III proofread the newly synthesized daughter strands and fix any mistakes from the replication process.
500
Oh no! You accidentally ingested a lethal poison, which consists of enzymes that degrade all of your ribosomes. Luckily for you, there is are 2 different antidotes for this poison, both of which can stop the enzymes from destroying ribosomes. The effectiveness of the first antidote depends on the concentration of ribosomes (which are the poisonous enzyme’s substrate), but the effectiveness of the second antidote does not. a) Knowing this, state what type of enzyme inhibition each antidote uses and explain how you know. b) Which antidote would be better to take and why?
a) The 1st antidote uses competitive inhibition. We know this because the effectiveness of a competitive inhibitor depends on the concentration of the enzyme’s substrate. Increasing the substrate concentration will decrease the effectiveness of the competitive inhibitor, since it competes with the substrate for the enzyme’s active site. The 2nd antidote uses non competitive inhibition, since its effectiveness does not depend on the substrate’s concentration (since non competitive inhibitors don’t compete with the substrate for the active site - they bind to a different site on the enzyme). b) It would be safer to take the 2nd antidote, since it is a non-competitive inhibitor. If you take the 1st antidote, then there is a chance that it won’t be effective if ribosome concentration is high.
500
Chelsea is running a marathon and her body is not getting enough oxygen. Explain what her body will do to adjust to this with respect to cellular respiration. What will be a consequence of this ‘adjustment’ that Chelsea will feel the next day?
Since Chelsea isn’t getting enough oxygen, her body cannot performer aerobic respiration (steps 2,3,4 of cellular respiration). So, she will switch to lactic acid fermentation, which is when the NADH made in glycolysis are oxidized to NAD+. The purpose of this is to regenerate NAD+, which can then be used in glycolysis to generate some energy. A product of lactic acid fermentation is lactic acid, which will make Chelsea feel sore the next day.
500
A) Fill in the blanks. Neurotransmitters are released from the ___ neuron. They cross the ___ and bind to receptors on the ___ neuron. Afterwards, the neurotransmitters can be degraded by an enzyme, or they can be taken back to the neuron that they originally came from via a re-uptake transporter (which is also an enzyme). B) Based on the information given in part A, state 4 ways in which a drug can interfere with neurotransmitters.
A) pre-synaptic, synapse/synaptic cleft, post-synaptic. B) A drug can block/speed up NT release, block the NT from binding to the receptor, inhibit the enzyme the degrades the NT, inhibit the re-uptake transporter.
500
Read each of the following scenarios and based on the given symptoms, state which part of the BRAIN is malfunctioning/injured: Person A cannot interpret what he is seeing. Person B has trouble with balance. Person C cannot initiate speech and has trouble walking. Person D is having trouble hearing.
Person A - occipital lobe Person B - cerebellum Person C - frontal lobe Person D - temporal lobe
500
A) How are the lac and tryptophan operons similar? How are they different? B) If a person is vegan, what can you predict about the lac operons in their body cells?
A) Similarities - both operons have a repress protein, a promoter region, an operator, and a signal molecule. Differences - in the lac operon, the signal molecule binding to the repressor will cause activation of the gene, while in the trp operon, the signal molecule binding to the repressor will cause the gene to be turned off. B) Vegan = don’t consume dairy products = low lactose diet. Low lactose means that the repressor protein (lac I) will be bound to the gene, blocking its transcription = the gene will be turned off.