Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

MCAT Biology > Frequent Mistakes > Flashcards

Frequent Mistakes Flashcards

1
Q

At what C does galactose differ from glucose?

A

C4

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

At what C does mannose differ from glucose?

A

C2

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

How does fructose compare to glucose?

A

same as glucose but with a ketone group on C2

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

What is maltose?

A

2 glucose (alpha)

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

What is sucrose?

A

fructose + glucose (alpha)

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

What is lactose?

A

galactose + glucose (beta)

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

What kind of glycosidic linkages are not digesteable by humans?

A

Beta (opposite sides)

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

What is urea’s chemical structure?

A

H2N-C=O-NH2

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

What is a sphingolipid?

A

Sphingoside backbone + fatty acid chains + polar head group

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

What are the 4 types of sphingolipids?

A
  1. Ceramide
  2. Sphingomyelins = sphingophospholipids
  3. Glycosphingolipids
  4. Gangliosides
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What are the 2 types of glycosphingolipids?

A
  1. Cerebrosides

2. Globosides

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

What is a sphingoside backbone?

A

Long C chain + HO-C-C-NH3-C-OH (with a double bond near the polar head group)
The NH3 is also bound to a O=C-R –> the fatty acid residue

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

What is a sphingomyelin? Does the head group have a net charge?

A

Sphingolipid with a phosphocholine group bound by a phosphodiester bond
Phosphocholine group = phosphatidylethanolamine or phosphatidylcholine
No net charge!

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

Is a glycosphingolipid a phosphosphingolipid?

A

No

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

Is a sphingomyelin a phosphosphingolipid?

A

Yes

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

What is a cerebroside? Does it have a net charge?

A

Glycosphingolipid with a single sugar as a head group

No net charge

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

What is a globoside? Does it have a net charge?

A

Glycosphingolipid 2 or more sugars as a head group

No net charge

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

What is a ganglioside? Does it have a net charge?

A

Sphingolipid with an oligosaccharide + 1 or more N-acetylneuraminic acid (NANA = sialic acid) as a head group
Yes, it is negatively charged

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

Is a ganglioside considered a glycosphingolipid?

A

Yes, because it has a glycosidic bond

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

What elements does a phospholipid contain?

A

Fatty acid tail + head: phosphate + alcohol

Linked by phosphodiester bonds

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

What is the difference between primary and secondary active transport?

A

Primary: requires ATP hydrolysis to move substances across their chemical gradients
Secondary: makes use of concentration gradients set up by primary active transport

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

What does a hydrolase enzyme do?

A

catalyze hydrolysis

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

What does a lyase enzyme do?

A

enzyme that catalyzes a catabolic reaction without water

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

What is facilitated diffusion? What molecules utilize this?

A

spontaneous passive transport → large, polar, and/or charged molecules through ion channels (proteins)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What is a nucleosidic bond?

A

bond between the nitrogenous base and the pentose sugar at the 1’ Carbon –> C-N bond forms

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What bond forms in a peptide bond?

A

C-N

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What is required for an amino acid to act as a buffer?

A

the pH needs to be near one of its pKas

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What is the molecular weight of a peptide bond?

A

18

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

What kind of molecules will cluster around disulfide bonds?

A

HYDROPHOBIC molecules will cluster around disulfide bonds because they form the nucleus of the hydrophobic core of the folded protein.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

Are allosteric interactions covalent?

A

No

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

Describe competitive inhibition

A

Km increases
Vmax stays the same
Lines intersect on the y-axis
Overcome by: increasing [S]

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

Describe noncompetitive inhibition

A

Km stays the same
Vmax decreases
Lines intersect on the x-axis
Overcome by: increasing [E]

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

Describe uncompetitive inhibition

A 
Km decreases (due to better binding efficiency - prevent release of substrate = This makes it look like the substrate has greater affinity for the enzyme than it would otherwise, which lowers Km- as a result of Le Chatelier's principle and the effective elimination of the ES complex thus decreasing the Km which indicates a higher binding affinity).
Vmax decreases (as a result of removing activated complex)
Lines do not intersect, they are parallel
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

Described mixed inhibition

A

Km will increase or decrease (depending on binding affinity)
Vmax decreases
Lines will intersect at neither axis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

Which is an organic molecule: coenzyme or cofactor?

A

Coenzyme

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

Can heat denature fatty acids?

A

NO

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

What 3 processes are endonucleases used for?

A

DNA repair, Southern blotting and gene therapy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

What is proofreading? When does it happen? To whom? What is the key enzyme?

A

happens in the S phase for both prokaryotes and eukaryotes
fixes mismatched base pairs
key enzyme: DNA polymerase (distinguishes between strands thanks to methylation)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

What is mismatch repair?When does it happen? What is the key enzyme?

A

happens in the G2 phase
fixes mismatched base pairs that were missed by the proofreading process
key genes: MSH2 and MLH1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

What is nucleotide excision repair? When does it happen? What is the key enzyme?

A

happens in G1 and G2
repairs dimers
key enzyme: excision endonuclease

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

What is base excision repair? When does it happen? What is the key enzyme?

A

happens in G1 and G2
no double helix deformation (no base pair mismatch) but still not the base you want. ex: uracil inserted in DNA; take the one base out, then the whole thing and then reinsert the whole thing
key enzyme: glycosylase and AP endonuclease

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

What do primers do in PCR?

A

complementary to the DNA that attach at the 3’ end of each strand

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

What enzyme is involved in PCR?

A

DNA polymerase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

What is Southern blotting?

A

: DNA is cut by restriction enzymes and then separated by gel electrophoresis → then DNA fragments are transferred to a membrane and probed with many copies of single stranded DNA sequences → probes are labeled and will indicate when they have bound to the complementary DNA strand

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

What happens during DNA sequencing?

A

uses ddNTPs → modified N+sugar nucleotides that contain a hydrogen at C-3’ rather than OH → once one of these bases is added, the polymerase can no longer add to the chain → sample will contain many fragments → separated by gel electrophoresis by size, so the sequence can then be read

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

Nucleotides vs nucleoside?

A 
nucleoside = pentose + base
nucleotide = nucleoside + phosphate group
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

3 Differences between prokaryotic and eukaryotic gene control?

A

Multiple transcription factors are necessary for eukaryotes
In eukaryotes RNA undergoes further modifications before translation
In eukaryotes, alternative splicing occurs so that multiple different proteins can be translated from the same primary message

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

1 similarity between prokaryotic and eukaryotic gene control?

A

both depend upon specific protein-DNA interactions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
49
Q

2 features of fatty acids found in eukaryotes?

A

EVEN number of Cs!

cis double bonds, never trans!

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
50
Q

Effects of cholesterol on fluidity of plasma membrane?

A

At physio temperatures: increasing cholesterol content would decrease fluidity
At cold temperatures: increasing cholesterol would increase fluidity because it keeps the phospholipids from clumping together

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
51
Q

From where does exhaled CO2 derive its O2?

A

from carbohydrates

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
52
Q

What is the difference between synthase and synthesaze enzymes?

A

Synthase does not require outside energy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
53
Q

What does a dehydrogenase enzyme do?

A

transfers H- to an electron acceptor (NAD+, FAD, …etc.) → oxidizes its substrate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
54
Q

What does a reductase enzyme do?

A

reduces its substrate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
55
Q

What does a carboxylase enzyme do?

A

COOH is added to the molecule

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
56
Q

What is the effect of uncouplers?

A

Uncouplers inhibit ATP synthesis without affecting the ETC, which means that the body will need to burn more fuel (like glycogen and use more O2) to maintain the H+ gradient!

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
57
Q

Why is acetyl-CoA so energetic?

A

has very high energy thioester bonds.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
58
Q

Can acetyl-CoA be converted to glucose?

A

No!

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
59
Q

Can fatty acids be converted to glucose?

A

Those with an odd number of Cs, yes!

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
60
Q

What organ is most sensitive to O2 deprivation?

A

Brain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
61
Q

What kind of molecules are stored within the cell?

A

Polar

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
62
Q

What is hyperplasia?

A

increased cell production in a normal tissue or organ.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
63
Q

What is an agonist?

A

binds to a receptor to increase what the receptor does; stimulate it

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
64
Q

What does mitosis always produce?

A

Diploid cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
65
Q

What is necessary for a gas to flow from one place to the other?

A

the partial pressure of the gas in the first place must be higher than that in the place it’s going to.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
66
Q

What is a test cross?

A

Always with a homozygous recessive genome

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
67
Q

What does polymorphism mean?

A

phenotypic variations within the same species of the same population

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
68
Q

What are the conditions for the Hardy Weinberg equilibrium? 5

A
  1. Large pop
  2. No mutations
  3. Random mating
  4. No migrations
  5. Equally successful genes
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
69
Q

What did the Griffith experiment show?

A

bacteria can acquire new genetic material

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
70
Q

What did the Avery-McLeod experiment show?

A

DNA is the genetic material (DNA degradation)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
71
Q

What did the Hershey Chase experiment show?

A

Confirmed DNA is the genetic material: radiolabeled DNA in infected bacteria

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
72
Q

What is genetic leakage?

A

Flow of genes between species through hybrid offspring that are fertile

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
73
Q

What is a monohybrid cross? What is the genotype ratio?

A

crossing 2 heterozygotes with complete dominance

1:2:1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
74
Q

What is hybrid breakdown?

A

2nd generation is inviable or sterile

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
75
Q

What is gene flow?

A

gene flow (also known as gene migration) is the transfer of alleles or genes from one population to another

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
76
Q

What is the basolateral membrane?

A

Faces toward the interstitium and away from lumen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
77
Q

What is the order from blood vessel to tissue?

A 
Blood vessel
Capillary endothelial cell
Interstitium (with fluid)
Basolateral membrane
Epithelial cell 
Apical membrane
Lumen
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
78
Q

What is Mendel’s first law?

A

Segregation: alleles segregate during meiosis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
79
Q

What is Mendel’s second law? What is the problem with it?

A

Independent assortment

Problem: linked genes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
80
Q

Skeletal muscle: multi or uninucleated?

A

Multi

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
81
Q

What are the differences between red and white muscle fibers?

A

Red: slow-twitch: carry out ETC
White: fast twitch: rely on anaerobic metabolism

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
82
Q

Smooth muscle: multi or uninucleated?

A

Uni

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
83
Q

Cardiac muscle: multi or uninucleated?

A

Uni (sometimes bi)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
84
Q

Describe muscle contraction? 12 steps

A
  1. Acetylcholine release at the neuromuscular junction
  2. Ach binds to sarcolemna = depolarization
  3. Depolarization spreads through T-tubules
  4. Ca2+ is released by the sarcoplasmic reticulum
  5. Ca2+ binds to troponin
  6. Shift in tropomyosin= exposure of myosin binding sites on actin
  7. Myosin binds to actin
  8. Myosin releases ADP + Pi = contraction
  9. Ach is degraded at synapse
  10. Ca2+ is resorbed by sarcolemna
  11. ATP binds to myosin= actin release
  12. ATP is hydrolyzed to ADP + Pi = recocking of myosin head
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
85
Q

What is the relationship between the thymus and Ach?

A

Thymus has Ach receptors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
86
Q

What are the 5 cell types that do not undergo mitosis?

A
  1. Neurons
  2. Red and white blood cells
  3. All muscle cells (3 types)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
87
Q

Out of all of the endocrine system hormones, which ones are steroid hormones? 5

A 
Glucocorticoids
Aldosterone
Estrogen
Progesterone
Testosterone
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
88
Q

What happens in the proximal convoluted tubule of the nephron? 2

A
  1. Bulk resorption of glucose, aas, vitamins, salt, and water
  2. Absorption of HUNK: H+, urea, NH3, and K+
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
89
Q

What happens in the descending limb of the loop of Henle of the nephron?

A

Water resorption

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
90
Q

What happens in the ascending loop of Henle of the nephron? What about in the diluting segment?

A

Salt resorption

Loop is thicker in diluting segment (mito) and can give extra salt to blood: active transport

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
91
Q

What happens in the distal convoluted tubule of the nephron? 2

A
  1. Salt resorption

2. Waste product (HUNK) absorption

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
92
Q

What part of the nephron is responsive to aldosterone?

A

DCT and collecting duct

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
93
Q

What part of the nephron is responsive to ADH?

A

Collecting duct

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
94
Q

What happens in the collecting duct of the nephron? What does it control?

A

Water resoption; controls urine concentration

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
95
Q

What is another name for coenzyme Q?

A

Ubiquinone

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
96
Q

Which involves crossing over: meiosis or mitosis?

97
Q

During which phase do the centrosomes migrate to the poles of the cell?

98
Q

During which phase do the chromatids or chromosomes migrate to the poles of the cell?

99
Q

Where does prokaryotic transcription take place?

100
Q

In what phase of the cell cycle does eukaryotic trasncription occur?

101
Q

What does RNA polymerase I synthesize in eukaryotes?

102
Q

What does RNA polymerase II synthesize in eukaryotes?

103
Q

What does RNA polymerase III synthesize in eukaryotes?

104
Q

What enzyme synthesizes RNA in prokaryotes?

A

RNA polymerase: only 1 for all types of RNA

105
Q

What are the 2 actions to process hnRNA after transcription in prokaryotes?

A
  1. 5’ cap = methylguanosine

2. 3’ poly A tail

106
Q

What is the H zone of the sarcomere?

A

Thick filaments ONLY

107
Q

What is the A band of the sarcomere?

A

Thick filaments in their entirety

108
Q

What is the M line in the sarcomere?

A

Cuts the thick filaments in half

109
Q

What is the I band of the sarcomere?

A

Thin filaments ONLY

110
Q

What is GABA? What is its other name?

A

Neuron inhibitor both pre and post synaptically

gamma-aminobutyric acid

111
Q

What does a GABA deficiency usually cause?

A

Stress, panic, anxiety

112
Q

What can cause a downregulation of GABA receptors?

A

Chronic alcohol consumption –> seizures and tremors once you stop drinking

113
Q

What is the pathway of a newly synthesized protein?

A

rough ER → cis side of Golgi apparatus → trans side of Golgi apparatus

114
Q

What is nondisjunction in meiosis?

A

incorrect segregation of homologous chromosomes or sister chromatids → one daughter cell ends up with 2 copies of related genetic material and the other receives zero.

115
Q

What does angiogenesis mean? What is it necessary for?

A

formation of new blood vessels → necessary for most tumors to grow

116
Q

What would be the effect if the cell was stuck in G1?

A

remaining in G1 would significantly affect membrane transport (surface area is too small compared to volume)

117
Q

What are the spindle fibers made of? What is their role? When does this happen?

A

Spindle fibers are made of microtubules

They attach to the centromeres → kinetochores are the attachment points; this happens in prophase!!!

118
Q

What is the role of centrioles?

A

they are the ones that create the spindle fibers and align at two poles of the cell

119
Q

What is synapsis?

A

pairing of homologous chromosomes

120
Q

What is the zona pellucida?

A

glycoproteins on ovum for sperm binding

121
Q

What is the corona radiata?

A

layer of cells that adhered to the oocyte during ovulation

122
Q

What is a Double crossover?

A

two recombination events → “middle” portion of each chromosome is exchanged, while the ends remain the same.

123
Q

What is the one organ that is generated from 2 different germ layers?

A

Adrenal glands come from both the ectoderm (adrenal medulla) and the mesoderm (adrenal cortex)

124
Q

What is necrosis?

A

process of cell death as a result of injury

125
Q

Dilate bronchi and pupils: parasympa or sympa NS?

126
Q

What is retrograde neurotransmission?

A

refers to the process by which a retrograde messenger, such as anandamide or nitric oxide, is released by a postsynaptic dendrite or cell body, and travels “backwards” across a chemical synapse to bind to the axon terminal of a presynaptic neuron.

127
Q

What is the Downstroke of action potential?

A

Repolarization

128
Q

Can the TLC of the lungs be measured?

A

No because of residual volume

129
Q

How are the lungs of premature babies different?

A

They lack surfactant

130
Q

What does a virus being dormant mean?

A

the virus’ inserts its genetic material into the host cells, but the genes aren’t expressed. BUT, an infection might be active without symptoms → the genes ARE being expressed, but maybe they code for non-harmful proteins, hence the lack of symptoms.

131
Q

If plants are genetically modified, is this innate or active immunity?

132
Q

Where is bile produced, stored, and concentrated?

A

Bile is produced in the liver, stored and concentrated in the gallbladder, and released in the duodenum through the biliary tree upon stimulation by CCK

133
Q

Where does protein digestion start? Where do carbs and fat digestions start?

A

Protein digestion starts in the stomach; carbohydrate and fat digestion starts in the mouth

134
Q

What happens when the stomach secretes too much HCl?

A

the enzymes for absorption in the rest of the digestive tract will not work because the pH will be too low

135
Q

Under normal conditions, the nephron creates urine that is hyper or hypo tonic to the blood?

136
Q

What are the 3 portal systems?

A

Kidneys (different types of transfer in each cap bed: filtration + reabsorption/secretion)
Hypophyseal (between hypothalamus and anterior pituitary)
Hepatic (between gut tube and liver)

137
Q

What are the 5 layers of the epidermis from highest to lowest? (Come, Let’s Get Sun Bathed)

A 
Stratum Corneum
Stratum Lucidum
Stratum Granulosum
Stratum Spinosum
Stratum Basale
138
Q

Where are Ach receptors located in the muscle cell?

A

Sarcolemma

139
Q

What is the difference between a frequency of summation and tetanus?

A

frequency of summation (describes muscle): neuron fires in succession, and muscle does not have time to relax fully
tetanus (describes muscle): max contraction of the muscle

140
Q

What will be the effect of having an excess X chromosome?

A

Excess X chromosomes will have mild phenotypic consequences because of dosage compensation

141
Q

What part of the muscle cell releases the Ca2+?

A

The sarcoplasmic reticulum

142
Q

What will increase the force of a muscle contraction?

A

An increase in the number of cells contracting

143
Q

What energy source does the muscle utilize when O2 runs out?

A

creatine

myoglobin

144
Q

What is Endochondral ossification?

A

cartilage into bone → long bonds

145
Q

What is Intramembranous ossification

A

mesenchyme into bone → this is how the skull is formed

146
Q

What is the hallmark of a dominant trait?

A

2 parents with a trait have offspring without the trait

147
Q

What is the hallmark of a recessive trait?

A

2 parents without a trait have offspring with the trait

148
Q

What is an example of the founder effect?

A

sending a small population to Mars

149
Q

What are 2 examples of genetic drift?

A

people with a certain type of alleles die, random mutations, etc.

150
Q

What is directional evolution?

A

a drastic and extreme change in phenotype.

151
Q

Which protein structure is the most important for enzymatic function? Why?

A

the tertiary structure

Most inactive enzymes have modifications of the active site, which is part of the tertiary structure

152
Q

What is a lysosome? What process is it involved in?

A

membrane bound structures containing enzymes to break down substrates and waste products → involved in phagocytosis

153
Q

The more nitrogen in a molecule, the more…?

154
Q

Is tyrosine hydrophilic of phobic?

155
Q

Which is more conformationally demanding: alpha helix or beta sheet?

A

Alpha helix

156
Q

What kind of secondary structure do amyloid plaques have?

A

Aggregates of beta sheets with hydrophobic residues

157
Q

When the pH is below the pKa of an amino acid, is it deprotonated or protonated?

A

Protonated

158
Q

Which 2 aas have a chiral center in their side chain?

A

Isoleucine and threonine

159
Q

What is Km equal to?

A

k2 + k3/k1

160
Q

What is the equation to calculate V from Vmax and Km?

A

V = Vmax . [S] / (Km + [S])

161
Q

When does an enzyme need to be tightly bound to its substrate?

A

when it needs a more tightly controlled catalytic environment. If you have a substrate that can easily react with something you don’t want it to, it makes sense to bind it really tightly to hide it from the external environment → the enzyme as protecting it while it reacts.

162
Q

How does the graph for V vs [S] look when the substrate induces cooperative binding?

A

the [S] vs V plot is sigmoidal (instead of hyperbolic) because after 1 molecule binds, the affinity increases and v increases (Km does NOT)

163
Q

What are the reactants when beta amylase cleaves amylose?

164
Q

What are the reactants when alpha amylase cleaves amylose?

A

maltose + glucose

165
Q

What is a furanose?

A

carbohydrate with a 5-membered ring

166
Q

What is a pyranose?

A

carbohydrate with a 6-membered ring

167
Q

What is an aldose?

A

carbohydrate with only one aldehyde group

168
Q

What vitamin is cholesterol a precursor to?

169
Q

What are glycerophospholipids made of?

A

polar head group (glycerol) and 2 fatty acids + phosphodiester bond to head group

170
Q

Can tryacylglycerol H bond?

171
Q

What are trans fats?

A

Unsaturated fatty acids

172
Q

Usually, does adding double and triple bonds increase boiling point?

173
Q

What increases the fluidity of the membrane: saturated or unsaturated fatty acids?

A

Unsaturated

174
Q

What are the molecules least likely to contain aromatic rings?

175
Q

How is cDNA formed?

A

from processed mRNA by reverse transcription

176
Q

When does cytosine become uracil?

A

In the presence of heat

177
Q

What energy form is necessary for DNA replication?

178
Q

What can a thymine dimer be caused by?

179
Q

How do restriction enzymes work?

A

They cleave DNA at specific sites: they recognize and cleave palindromic regions of DNA → regions in which 2 complementary strands have the same sequence

180
Q

What is the order to remember the 4 types of DNA repairs?

A
  1. Proofreading
  2. Mismatch
  3. Nucleotide excision
  4. Base excision
181
Q

At which point in the cell cycle would a DNA double-strand break, if left unrepaired, affect both chromatids in a pair of sister chromatids?

A

G1, because it happens before the S phase, in which synthesis takes place.

182
Q

What is the difference between B-DNA and Z-DNA (not biologically relevant)?

A

order of major and minor grooves and how spaced out they are

183
Q

In PCR, when are low and high temperatures needed?

A

Low: enzyme activity High: DNA denaturation = separating the 2 strands

184
Q

How many base pairs in the human genome?

185
Q

What is the theoretical maximum recombination frequency?

186
Q

What is the start codon?

187
Q

When determining the mRNA sequence, how should it match the DNA?

A

it should match antiparallel → 5’ → 3’ on the DNA will match the 3’ → 5’ on the mRNA

188
Q

What would happen if antisense mRNA is present in the cytoplasm?

A

it will bind to the newly synthesized mRNA, form a double stranded RNA molecule → cannot be transcribed by ribosome

189
Q

Where does a mutation need to be to modify the amount of protein produced?

A

The promoter site

190
Q

Does mRNA happen prior or after the ribosomal units binding?

A

mRNA binding precedes the binding of the 2 ribosomal units!

191
Q

What happens if there is deamination of DNA adenosine?

A

It incorrectly pairs with cytosine

192
Q

What happens if thymine in DNA is in its enol form?

A

It incorrectly pairs with guanine

193
Q

What does the RNA do to protect itself?

A

Single stranded nucleic acids are especially vulnerable to attack, so the RNA usually assumes a 3D conformation in a very tight hairpin loop or lariat where RNA binds to itself.

194
Q

What does it say about the cellular environment if a cell lyses?

A

it was in a hypotonic environment

195
Q

Which are the most rapid molecules in the cell membrane?

A

lipids moving within the plane of the membrane

196
Q

What should the temperature be when 2 DNA strands have weak pairing?

A

Lower than normal because higher temperatures disrupts the H bonds

197
Q

What is mesenchymal tissue?

A

Embryonic connective tissue

198
Q

What do tendons connect?

A

Bones and muscles

199
Q

What is chondrin? What cells secrete it?

A

The elastic matrix that makes up cartilage

Chondrocytes secrete it

200
Q

What do ligaments connect?

A

Bones and bones

201
Q

What does a flexor muscle do?

A

Decreases the angle across a joint

202
Q

What does an extensor muscle do?

A

Increases the angle across a joint

203
Q

What does an abductor muscle do?

A

Moves a part of the body away from the midline

204
Q

What does an adductor muscle do?

A

Moves a part of the body toward the midline

205
Q

In which parts of the body do medial and lateral rotation happen?

206
Q

Which one is easier to establish: paternity or maternity?

A

Paternity is easier to establish than maternity because to establish maternity either the child’s alleles must be compared to both mother and father, or mitochondrial DNA must be used

207
Q

What is pinocytosis?

A

Mode of endocytosis in which the cell inputs large amounts of water

208
Q

Does the mitochondria use more maternal or paternal DNA?

A

more maternal DNA than paternal DNA, but still uses both

209
Q

What are the 3 factors affecting membrane fluidity? Explain

A
  1. Temperature: low decreases it, high increases it
  2. Cholesterol: at low temps in increases it, at high it decreases it
  3. Fatty acids: saturated decreases it, unsaturated increases it
210
Q

Where are sphingomyelins found?

A

In myelin producing cells and myelin: Schwann cells (PNS) and oligodendrocytes (CNS)

211
Q

What is a ceramide?

A

Sphingosine backbone bound to a fatty acid residue that has an amide

212
Q

Is tryacylglycerol hydrolizable?

213
Q

What is a phosphodiester bond?

A

P bonded to:
2 OR
=O
OH

214
Q

What is the lipid bilayer like?

A

It has phospholipids with head groups pointing on the inside and outside of the cell and the hydrophobic tails connecting in the middle of the membrane

215
Q

Are sphingolipids hydrolizable?

216
Q

What is the structure of a wax?

A

Ester with two very long R groups on each side

217
Q

What kind of biomolecules are prostaglandins? What is their role?

A

Lipids

Autocrine and paracrine hormones that regulate cAMP levels

218
Q

What is the structure of steroids like?

A

3 cyclohexane rings + 1 cyclopentane ring

219
Q

What is the role of terpenes?

A

Signaling molecules

220
Q

In the nephron, where is Na+ resorption active?

A

Thick segment of ascending limb of the loop of Henle

221
Q

What is the difference in sugars in DNA and RNA?

A

DNA contains the sugar deoxyribose, while RNA contains the sugar ribose. The only difference between ribose and deoxyribose is that ribose has one more -OH group than deoxyribose, which has an H attached to the second (2’) carbon in the ring.

222
Q

Is cellulose digestible by humans? Why?

A

No because of beta linkage

223
Q

What are amylose annd amylopectin?

A

Starches to store carbs

224
Q

What does amylopectin’s structure resemble?

225
Q

What is the role of the epithelial cells in the lungs?

A

They are responsible for the cough reflex, and are not responsible for alveolar gas exchange

226
Q

In what embryogenesis stage are the 3 germ layers formed?

A

Gastrulation

227
Q

How to pick the best PCR primer?

A

Should have the most C and G to be more tightly bound

228
Q

Does Km depend on substrate concentration?

229
Q

Does transport capacity depend on substrate concentration?

230
Q

What does Km represent?

A

Substrate concentration at which the reaction rate is 1/2 of Vmax

231
Q

What kind of amino acids are used during ribosomal protein synthesis?

A

L-isomers!!

232
Q

How do bacteria adapt to a new environment?

A

Regulation and control of gene expression

233
Q

Which is expressible: euro or heterochromatin???

A

Eurochromatin!

234
Q

How will have fewer pigments of a certain color affect the signals sent to the brain regarding that color?

A

Fewer signals will be sent

235
Q

How to go from Fischer to Haworth?

A
  1. Find carbon #5 –> the O on it, will be part of the ring
  2. C5 will be on the left of it in the ring
  3. Everything on the right hand side in the Fisher projection will go down on the Haworth
  4. CH2OH is always UP on C5
  5. The OH on C1 will either go up or down: racemic mixture
236
Q

What is the difference between alpha and beta D glucose?

A

Alpha: OH points down on C1
Beta: OH points up on C1

237
Q

What is the difference between D and L glucose?

A

Different stereochemistry at all Cs

238
Q

Which 5 amino acids are charged at physiological pH?

A

Negative: glutamic acid and aspartic acid
Positive: histidine, arginine, and lysine

MCAT Biology (18 decks)

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