Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

MCAT Practice Test 4 > Bio/Biochem > Flashcards

Bio/Biochem Flashcards

(77 cards)

Start Studying
1
Q

What effect does leptin have on the body?

A

Leptin decreases appetite.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What happens as a result of reduced blood insulin levels?

A

Decreased uptake if blood glucose by muscle cells
Increases conversion of glycogen into muscle glucose
Increased utilization of fatty acid as fuel

Insulin levels are reduced at times of low blood glucose concentration in order to conserve glucose for brain use.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What does glucagon do?

A

Promotes conversion of glycogen into glucose.

Glucose is all gone so need to make more available.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are some things that happen during extreme starvation?

A

Increased resistance to insulin

Elevated plasma cortisol, inability to effectively undergo thermogenesis, unrestrained appetite.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What does cortisol do?

A

Steroid hormone that is known as the fight or flight hormone.
Released during times of stress and increases heart rate, blood pressure, blood glucose, respiration and muscle tension.
Temporarily shuts down not needed body systems like digestion and reproduction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What does an osteoclast do?

A

Break down bones. This releases calcium from bone into blood.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What does calcitonin do?

A

Lowers blood calcium, it is secreted in response to calcium elevations

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What does an osteoblasts do?

A

Builds bone. This decreases calcium in the blood because it is being put into bone.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

How do you remove biological activity from a hormone?

A

Amino terminus must be destroyed.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What must a substance be to be excreted in the urine?

A

Water soluble.

Water insoluble compounds are either stored in the body, converted to water soluble products or eliminated in the feces.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What must a molecule go through to get into the urine?

A

A molecule must be filtered from the blood through the glomerulus and into the renal tubule for transport to the ureter and bladder.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is the Vasa recta?

A

A capillary bed in the kidney that gives the kidneys it’s oxygen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What are peritubular capillaries?

A

Capillary bed in the kidneys that are responsible for collecting nutrients

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What does the renal artery do?

A

Brings blood to the kidneys that is then filtrated.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What does the renal vein do?

A

Reabsorbs nutrients needed by the body from the filtrate of the kidneys and returns it to the heart.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is the renal cortex?

A

The outer shell of the kidney. The renal medulla is inside the cortex.
Nephron found between the cortex and medulla.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is the afferent arterioles?

A

Branch from the renal artery, which supplies blood to the kidneys. Feeds blood into the glomerulus.

Afferent arrives and efferent exits

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is the errerent arteriole?

A

Blood exits the glomerulus through the efferent arteriole.

Efferent exits

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What does the glomerulus do?

A

Main site of filtration. Takes blood and turns it into filtrate and lets the rest of the blood flow on. The fluid that leaks out of the glomerulus is called filtrate. This filtrate is caught in a capsule connected to the glomerulus called bowmans capsule.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Endothelial cells

A

Cells that make up the glomerulus. These cells are fenestrated which means they have small holes. This allows small molecules like a.a., glucose and sodium to come through and go into bowmans capsule

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Epithelial cells

A

Also known as tubule cells. Make up bowmans capsule

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Filtrate goes from the bowmans capsule to what?

A

The proximal tubule. Point of the proximal tubule is to allow some of the filtrate to be reabsorbed so the body doesn’t lose important things to urine like glucose and amino acids. There is a capillary system very close to the proximal tubule. ATP is used to ACTIVELY pump glucose and amino acids back into the capillaries. A little bit of the water is also pumped back into the capillaries.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What is the loop of henle?

A

Crosses border of the renal cortex of the kidney and the renal medulla.
Makes renal medulla salty by actively pumping salts out of the loop at the ascending part of the loop (the right side of loop). These salts being Na+, K+, Cl-. Makes medulla hypertonic and is done by actively pumping against a concentration gradient. The ascending part of the loop is NOT permeable to water. The descending part of the loop (left side) is ONLY permeable to water which causes water to want to leave the loop because of the surrounding salty medulla.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What is the distal tubule?

A

More things the body doesn’t want to lose are being reabsorbed into the blood and leaving this tubule. Proximal tubule is start of loop of henle and distal tubule is end of loop of henle. Filtrate is very concentrated at the end of the distal tubule. Filtrate then gets dumped into collecting ducts.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Collecting ducts
Collect the concentrated filtrate that contains all the things the body doesn’t want. Multiple distal tubules dump into one collecting duct. Collecting ducts go into the medulla. Anti diuretic hormones in the collecting duct determine how porous the duct is going to be. If it makes it very porous then more water can leave the collecting duct to be reabsorbed by the blood which makes the filtrate even more concentrated. The concentrated filtrate is now urine and is excreted from kidneys by the ureter which then goes to bladder and then is excreted by the urethra.
26
What are the haversian canals?
Series of microscopic tubes in the outermost region of bone called cortical bone that allow blood vessels and nerves to travel through them.
27
Higher concentrations of interstitial fluid protein has what effect on the interstitial pressure?
Higher concentration causes higher pressure increase because of the higher solute concentration causing water to diffuse to the higher solute concentration.
28
What does an increase of hydrogen ions (acidemia-low blood pH) in the blood do to hemoglobin?
Decreases hemoglobins affinity for oxygen. Someone with acidemia would have less saturated hemoglobin. A hemoglobin dissociation curve corresponding to an acidotic patient would be shifted to the right of the curve for normal pH
29
How are velocity and temperature related in enzymatic reactions?
They are directly proportional so when temp increases so does the rate of the reaction. However high temps can cause enzymes to denature, haunting the reaction and causing a sharp decrease in velocity. This is why a graph will begin with an upward slope and then a descending slope after denaturation.
30
When in the cell cycle does nuclear DNA replicate?
Only replicates during S-phase
31
What is the net number of ATP molecules synthesized by an obligate anaerobes per molecule of glucose?
2 ATP. An obligate anaerobes must live WITHOUT oxygen in order to survive. They produce ATP via fermentation, which includes both glycolysis and the reactions necessary to regenerate the NAD+ necessary for glycolysis to continue.
32
How many molecules of ATP do aerobic organism produce from one glucose molecule?
Net 36 ATP
33
How many molecules of ATP does glycolysis produce?
2 ATP Also produces 2NADH 2 pyruvate
34
What type of cells has the most mitochondria?
Skeletal muscle cells. | Mitochondria amounts are based on how much energy that tissue needs
35
As non polar protein groups cluster in water, the water experiences what effect to entropy?
An increase in entropy. Because so solvation later doesn’t have to be as big. Water molecules are freed up in order to react with other molecules which is an increase in entropy.
36
What is secondary structure of proteins determined by?
Local hydrogen bonds NOT HYDROPHOBIC EFFECT. Hydrophobic interactions have a larger role in tertiary structure.
37
Gibbs free energy formula.
Increase in entropy indicates a lesser Gibbs free energy value. DeltaG=DeltaH-TdeltaS G=Gibbs free energy H=enthalpy T=temp in Kelvin S=entropy
38
What division of the nervous system is responsible for the coordinated movement of food through the esophagus?
The autonomic nervous system. Swallowing is initially under voluntary control but through the esophagus it is involuntary
39
Muscle contraction is dependent on what?
Release of calcium.
40
What cells derive from the neural crest?
Adrenal medulla, Schwann cells and melanocyte cells.
41
What is the neural crest derived from?
The ectoderm
42
What is a morula?
16-32 cells(blastomeres) formed by cleavage of the zygote. Precedes the blastocyst Looks like a mullberry
43
What is a trophoblast?
Cells on the outside during compaction of a morula
44
What is an embryoblast?
Cells on the inside during compaction of a morula. These cells have become differentiated from the outer cells known as trophoblasts
45
What is a blastocoel?
Empty cavity that is formed when the inner cell mass(embryoblasts) compresses together during embryogenesis. It is now a blastocyst.
46
What is the primitive streak?
Mark of the beginning of gastrulation. Site where epiblasts start to migrate. Syrup on top of pancake.
47
Tri laminar disk
Formed at the beginning of gastrulation when the epiblasts migrate from primitive streak. Top layer is ectoderm, middle layer is mesoderm, endoderm is bottom layer.
48
What happens in the beginning of nerulation?
The tri laminar disk with its three layers further differentiate. The notochord is formed in the mesoderm. Ectoderm above notochord begins to change (thickens and forms the neural plate in the ectoderm)
49
What are the endoderm derivatives?
Forms gastrointestinal tract and | Lungs, liver, pancreas, esophagus, small intestines, large intestine
50
What are the mesoderm derivatives?
Form inner layers of skin, muscles, bones, and cardiac muscle, kidneys, bladder, ovaries, testes
51
What are the ectoderm derivatives?
Outer layer of skin, sweat glands, hair, nervous system, brain. Neural crest
52
What is codominance?
When two different dominant alleles at the same locus contribute to the genotype. The phenotype is the expression of both dominant alleles. Example is AB blood
53
What is the promoter gene/region?
Site of binding for the RNA polymerase.
54
What is the operator gene?
Binding site for the repressor. When a repressor is bound RNA polymerase cannot transcribe past the operator and the structural gene cannot be transcribed.
55
What is the structural gene?
Encodes for desired protein.
56
Where does the repressor bind?
Binds to the operator which prevents RNA polymerase from transcribing. An inducer can combat this by binding to the repressor so the operator is free and RNA polymerase can transcribe
57
How many bonds does A and T form?
Only two hydrogen bonds. G and C form three bonds. This means AT rich areas have fewer bonds and are easier to separate allowing them to denature easier.
58
Is the denaturation process endothermic or exothermic?
Endothermic because heat must be applied. Renaturation is exothermic. The reannealing process does not require additional energy so it is spontaneous.
59
What is recombination frequency?
Is used to determine genetic distance but cannot determine physical distance. Sometimes alleles cross over multiple times which makes it look like the recombination frequency is zero, this makes the alleles appear to be closer together than they actually are.
60
When does crossing over occur?
Prophase 1
61
What are centrioles composed of?
Microtubules. A pair of centrioles make up a structure called a centrosome. Centrioles are a part of the cytoskeleton.
62
Where do microtubules attach to chromosomes?
Centromeres.
63
What process directly produces GTP?
The citric acid cycle.
64
Glycolysis simplified
``` First step in cellular respiration 6 carbon glucose molecule to 2-3 carbon pyruvate molecules Requires 2 ATP Generates 4 ATP Net 2 ATP Occurs in the absence of oxygen. Pyruvate enters into citric acid cycle ```
65
Krebs cycle (citric acid cycle)
Pyruvate enters Krebs cycle and generates 2 ATP Requires oxygen Electron transport chain is next
66
Electron transport chain
Produces 34 ATP Requires oxygen NADH and FADH2 drive ETC
67
When in mitosis do tubulin polymers shorten?
Anaphase, when the chromosomes are pulled towards the two poles of the cell.
68
What is unique about self splicing group 1 and group 2 introns?
No proteins are involved in the splicing mechanism
69
What is unique about non number designated introns?
Their removal is catalyzed by a complex called a solo rosins and a uracil right snRNA is involved during the splicing reaction
70
What occurs when action potential induces muscle contraction?
Ca2+ is released into the cytosol; Ca2+ binds to troponin complex.
71
What happens when ATP binds to the myosin head?
Myosin releases Actin. ATP goes to ADP+Pi which releases the energy to put the myosin protein into a high energy state. “Spring loads” Then phosphate is released from myosin which releases energy of cocked position which pushes the actin. This is called a power stroke. Actin is the long filament ADP is finally released which puts you back at step one to restart
72
What does tropomyosin do?
Tropomyosin found on actin and is coiled around it and it attached to actin by troponin. Tropomyosin keeps the myosin head from being able to completely attach and move actin. Blocks myosin from crawling up the actin filament.
73
What does troponin do?
Troponin acts as nails to keep tropomyosin attached to actin. Troponin must change their shape in order to release tropomyosin so that the myosin head can push the actin filament. This occurs due to can influx of calcium ions. Calcium ions bind to troponin which changes its confirmation which releases tropomyosin. If calcium ion concentration becomes low then the troponin goes back to standard conformation and holds tropomyosin down so it blocks myosin again. This occurs in the cytosol.
74
What is acetylcholine?
Neurotransmitter that stimulates contraction of skeletal muscle.
75
What does isoosmotic mean?
Same concentration of particles. Means osmotic pressure is the same on both sides of membrane
76
What does hypoosmotic mean?
Solution with a lesser concentration of sulfite. Water would leave to go to the higher solute concentration
77
What does hyperosmotic mean?
Solutions that have increased osmotic pressure because it has more solutes than the other solution. Water rushes into it to try to even it out.

MCAT Practice Test 4 (2 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions