Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Sonja's MCAT Flashcards > Bio/Biochem > Flashcards

Bio/Biochem Flashcards

1
Q

Will a somatic mutation be inherited?

A

No, somatic mutations are not present in germ line and have 0% chance of being inherited by the child

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

What is a nuclear localization signal and what types of amino acids are likely to be included?

A

A amino acid sequence that “tags” proteins for entry into the cell nucleus. Often positively charged AAs outside on protein surface (K,R)

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

What is a signal sequence? What type of proteins have signal sequences?

A

Short peptide sequences that direct proteins to RER and secretory pathway. Most membrane bound and many transmembrane proteins have signal sequences.

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

Describe the structure of a steroid.

A

steroid core structure has 17 carbon atoms connected with 4 fused ring, three cyclohexanes and one cyclo pentane

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

What is the role of the sodium-potassium pump?

A

Maintain the resting potential of the membrane by pumping 3 Na+ out and 2 K+ in, using ATP to pump against the concentration gradient

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

What type of molecules enter the cell via simple diffusion?

A

Small, nonpolar (hydrophobic) molecules

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

What is the “promoter region” of a gene?

A

Protein binding site on DNA upstream of gene that initiate transcription. Example– TATA box (eukaryotes only)

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

What is a lipid raft?

A

cholesterol, glycoshingolipids, and protein receptor region freely floating in bilayer

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

What 3 ways do enzymes alter reaction rate?

A

1) Alter local pH
2) Colocalize substrates
3) Alter shape of substrate (does NOT change primary structure or free energy of rxn)

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

Describe the phosphodiester bond of DNA and RNA.

A

The 3’ -OH group of the sugar molecule binds to phosphate on 5’ of other sugar molecule

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

What is the two primary functions of cortisol in the body?

A

Cortisol (a glucocorticoid) raises blood sugar via gluconeogenesis and it suppresses the immune system.

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

What are two main symptoms of diabetes mellitus?

A

Frequent urination (glucose in urine, water unable to be resorbed) and catabolism of fatty acids, leading to weight loss/fatigue

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

Why is the replication of DNA considered semi-conservative?

A

The parent strand of DNA is kept intact, while the daughter stand is newly formed, meaning the parent DNA is half conserved for every cycle of replication

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

What type of bonds link nucleotides together in DNA strands?

A

phosphodiester bonds

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

What are the pyrimidines?

A

C,T. 1 ring structure

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

What are the purines?

A

A, G (pure As Gold), two rings (you always want more gold)

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

Describe the sequence of an action potential

A

resting, depolarization (VG na+ channels open, cell becomes positive), repolarization (VG K+ channels open, potassium goes out, cell becomes negative), hyperpolarization, resting membrane

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

What is the process of Ubiquitination?

A

The “kiss of death” process for a protein. Ubiquitin acts as tag for degradation of a protein by proteasomes

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

Where does the proton gradient build up in the ETC?

A

across the inner mitochondrial membrane

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

SNOW DROP

A

southern blot- DNA
northern blot- RNA
western blot- PROTEINS

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

What end of the amino acid are peptides added to during translation– n terminus or c terminus

A

amino acids are added to the c-terminus

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

how many molecules are there in 1 mole (aka avogadros number)

A

6 × 10^23 molecules per mole

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

What is actin?

A

the contractile filament of a muscle cell, has myosin binding site that is exposed after Ca2+ binds to troponin which pulls tropomyosin off site

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

what is the centrosome?

A

contains centrioles, organizes microtubules to maitian structure during cell replication

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
What type of cell wall do gram negative bacteria have?
single layer of peptidoglycan, double membrane
26
What type of cell wall do gram positive bacteria have?
thick layers peptidoglycan (single membrane)
27
Describe bacterial gene exchange via conjugation. Is it a feature of gram neg or gram pos bacteria?
one bacterium uses sex pilus to transfer gene to other bacterium, gene is plasmid referred to as Fertility factor or F factor. Gram neg.
28
How does a bacteria transfer its genes via transduction?
uses a virus like a bacteriophage
29
What happens in bacterial transformation?
bacteria takes up DNA from environment
30
Do prokaryotes have mitochondria?
no
31
Do prokaryotes have nucleus or organelles?
no
32
What is the difference between negative sense RNA virus and a positive sense RNA virus?
Negative sense RNA virus enter the cell and require replication of RNA complement strand prior to protein replication (via RNA replicase enzyme). Positive RNA virus can enter cell and begin translation immediately.
33
What is equipoise in clinical trials?
The knowledge that there is no superior treatment available. if during the study, one drug was obviously better, they would need to terminate study and give everyone the better treatment
34
What is unique about brown fat compared to white fat?
have a larger number of mitochondria, much more heat given off due to inefficiency of ETC (non shivering thermogenesis)
35
What is penetrance?
the proportion of the population carrying the allele that actually express the phenotype
36
What is variable expressivity?
individuals with the same genotype but have different phenotypes
37
What do the tail fibers of a virus do?
allow the virus to identify and infect the host cell
38
What is a neuronal tract?
a bundle of nerves in the CNS
39
What are Cyclin-dependent kinases?
molecules that facilitate the progression of the cell through the cell cycle. They work with cyclin to phosphorylate transcription factors. cyclin concentration increases during cell cycle. Checkpoints such as p53 inhibits cell growth and mutations can lead to cancer.
40
What triggers the influx of Na+ across the motor end plate during the depolarization of muscle fiber membrane?
ligand binding of acetylcholine
41
What triggers reentry of Ca2+ into sacroplasmic reticulum?
controlled by ryanocide receptors
42
How would you measure whether an enzyme used the competitive inhibition mechanism?
Keep enzyme concentration constant, measure velocity of reaction at increasing substrate concentration with and without inhibitor
43
What is the weight of 1 amino acid in Da?
110 Da
44
How do retrovirus' replicate ?
Use of reverse transcriptase and integrase. Viral RNA enters cell, RT creates cDNA strand, then dsDNA, which is integrated into host genome via Integrase, then replicate by the cell as normal RNA, which then can bud off from cell
45
How do retrovirus' replicate ?
Use of reverse transcriptase and integrase. Viral RNA enters cell, RT creates cDNA strand, then dsDNA, which is integrated into host genome via Integrase, then replicate by the cell as normal RNA, which then can bud off from cell.
46
What are the 3 stop codons?
UGA, UAA, UAG
47
What does Hill's Coefficient measure?
cooperativity. If greater than 1, protein exhibits cooperative binding. if equal to 1, means independent binding
48
Which has two rings: purines or pyrimidines?
purines
49
Which has the carbonyl, adenine or guanine?
guanine
50
Which has two carbonyls, thymine or cystosine?
thymine
51
What does cytochrome p450 do?
acts as a monooxygenase, oxidizing substrates (getting reduced itself)
52
During phosphorylation of a hydroxyl, what group is exchanged for a phosphate group?
the hydrogen atom, oxygen stays and forms bond to phosphate
53
What are transcription factors?
proteins that bind to regulatory domain of DNA in nucleus, regulating transcription
54
Where does Fatty acid oxidation take place?
mitochondria
55
Where does fatty acid synthesis take place?
cytosol (however pyruvate is converted into acetyl coA in the mitchondrial matrix, and the membrane is impermeable to acetyl coA, transfered via the carnitine acetyl transferase shuttle)
56
What does the carnitine shuttle do?
moves acetyl coA in and out of mitochondria for FAO and FAS
57
Describe the structure of malonyl coA, what does malonyl coA do?
enables fatty acid synthesis, is acyl coA plus a carbonyl group, which makes it higher energy, allows for decarboylation wnad then nuvleophilic attack to add additional carbons to FA. FA synthesis occurs in the cytostol
58
How do non competitive inhibitors alter Km and Vmax?
Km is the same, Vmax decreases (allosteric binding)
59
How does UN competitive inhibition alter Km and Vmax
decreases both, uncompetitive inhibitors bind only to enzyme substrate complex
60
How does UN competitive inhibition alter Km and Vmax
decreases both, uncompetitive inhibitors bind only to enzyme substrate complex
61
What are the three amino acids that are phosphorylated in euks?
Tyrosine (Y), serine (S), threonine (T)
62
What are the three amino acids that are phosphorylated in euks?
Tyrosine (Y), serine (S), threonine (T)
63
An amber codon is also known as? which ones are they?
STOP CODONS. UAG- U are great UGA- U got attitude UAA- U are awesome
64
What does RT-PCR measure?
reverse transcriptase PCR, converts RNA to DNA and a amplifies it
65
What is nondisjucntion?
when chromatids fail to separate (results in one cell with too many chromys, one with too few)
66
What is gel filtration chromatography?
AKA size exclusion chromatography
67
What is unique about the inactive X chromosome in females?
x-inactivation in females happens during early embryonic devlopment. it does replicate, just after the active one
68
What is EXCLUDED from the equilibrium constant equation?
pure solids and pure liquids-- their concentrations are considered infinity
69
What are tight junctions?
they form a continuous barrier between cells to (like the BBB). water tight seal
70
What are gap junctions?
gap junctions allow for direct chemical communication between cells
71
What are desmosomes?
spot welds, mostly join epithelial cells together (via cadherins)
72
Where does fatty acid oxidation occur?
mitochondria. FA are transported to mito from cytosol via the carnitine shuttle
73
What does the citrate malate shuttle do?
transports acetyl coA out of mito into cytosol for FA synthesis via citrate (membrane is impermeable to acetyl coA)
74
Where does glycolysis take place?
cytosol
75
Where does KREB cycle take place?
mitochondrial matrix
76
where does ETC take place?
protons are pumped across the IMM
77
How do competitive inhibitors alter Km and Vmax?
increase Km, no change in Vmax
78
What is affinity chromatography separate molecules based on?
their affinity to the protein to a ligand on the matrix
79
What is SDS PAGE?
electrophoresis that allows protein separation by mass (uses SDS detergent to get rid of charge)
80
What is the purpose of the lactic acid cycle?
to oxidize NAD+ for reuse in glycolysis during times of low O2. NADH is oxidized, pyruvate is reduced to lactate and NAD+ can go through glycolysis again to make ATP
81
What does calcitronin do?
produced by thyroid, decreases calcium resorption in response to high blood calcium levels (increase osteoblast activity, decrease osteoblast activity)
82
What does PTH do?
produced by parathyroid, increases calcium levels (increase osteoclast activity, decrease osteo blast activity)
83
What do ruffini cells respond to?
stretch
84
What do merkel cells respond to?
deep pressure
85
what do meissner cells respond to?
light touch
86
What is a Nonsense mutation?
insertion of a STOP codon (STOP the nonsense). Stop codons- UAG, UAA, UGA
87
What is the structure of maltose?
glucose-glucose by a alpha 1,4 bond
88
What is the structure of sucrose?
glucose and fructose by alpha 1,2 bond
89
What is the structure of lactose?
galactose and glucose by beta 1,4 bond
90
Where is glut 2 found? where is glut 4 found?
glut 2= liver (high km) | glut 4= everywhere else (normal km, gets saturated)
91
How is the pyruvate dehydrogenase complex controlled?
activated by removing a phosphate through PDH phosphatase | inactivated by adding a phosphate via PDH kinase

Sonja's MCAT Flashcards (4 decks)

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