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AK MCAT Review > Bio & Biochem > Flashcards

Bio & Biochem Flashcards

1
Q

What is special about the peptide bonds that form the backbone of proteins?

A

They are stable because they exhibit resonance stabilization

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2
Q

Innate Immune System

A

-Consists of nonspecific immune responses that provide general protection against specific pathogens that have been previously encountered and “remembered” -Symptoms: inflammation, vasodilation, blood vessel permeability, pain -team players: cytokines (signaling molecules) leukocytes (white blood cells)

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3
Q

Adaptive Immunity

A

-Opposite of Innate Immunity -Includes B cells and T cells, both of which are lymphocytes produced in the bone marrow and mature in the lymphatic system -Directed against particular pathogens to which the body has been previously exposed. These pathogens are “remembered” by specialized cells, leading to a quicker response in the case of a second exposure. Inflammation is NOT a specific protective mechanism

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4
Q

Passive Immunity

A

The transfer of antibodies from one individual to another

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5
Q

B Cell

A

recognizes antigens and secrete large amounts of antibodies inr esponse

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6
Q

Humoral Immunity

A

Hum body utilizes five classes of antibodies: IgA, IgD, IgE, IgG, IgM which differ in details of their heavy chain

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7
Q

T Cells

A

-mature in thymus, recognize cells that were our own but have been damaged by viral infection or malfunctioned in ways to turn them into cancer cells -subgroups of T cells directly attack compromised/foreign cells or mobilize response to them based on antigen fragments that are presented by Major Histocompatability Complex (MHC)

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8
Q

What makes an erythrocyte unique?

A

DO NOT contain DNA or membrane-bound nucleus -allows them to have more space for oxygen-carrying hemoglobin molecules -only engage in anaerobic metabolism (no mitochondria) -limited life span of 100 days

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9
Q

How are erythrocytes created?

A

created in bone marrow in response to erythropoietin (EPO): released from the kidney when erythrocyte levels are low -During development in bone marrow erythrocytes lose membrane-bound organelles including mitochondria and nucleus

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10
Q

Protein Kinase

A

add phosphate groups to its substrates

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11
Q

Protein Phosphotase 1

A

functions to remove phosphate groups from substrate

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12
Q

Oxioreductases

A

Catalyze oxidation-reduction reactions where electrons are transferred (i.e. hydride ions or hydrogen atoms)

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13
Q

Transferases

A

Catalyze transfer of a chemical group from a donor to an acceptor -donor is usually a cofactor charged with the group it is going to donate -Ex. phosphorylases & kinase

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14
Q

Hydrolases

A

catalyze reactions that involve cleavage of a molecule using water –> results in transfer of functional groups to water -Ex. amylases, proteases, lipases, phosphatases

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15
Q

Ligases

A

Used in catalysis where two substrates are stitched together via formation of C-C, C-S, C-O bonds while giving off water molecule

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16
Q

Isomerases

A

Catalyze reactions where substrate molecule is converted from one isomer to another Ex. glucose 6 phosphate isomerase

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17
Q

What is the most effective technique for sterilizing used laboratory materials?

A

Using an autoclave: brings materials to 120 degrees Celsius at pressure of over 2 atm, could kill almost anything

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18
Q

Single-crossover events vs. double-crossover events

A

Single-crossover: affects only the ends of chromosome arms Double-crossover: can affect segments in the middle of chromosomes

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19
Q

Which muscles types does the troponin complex function?

A

-skeletal and cardiac muscles

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20
Q

Gluconeogensis

A

generation of glucose from non-carbohydrate carbon substrates -insulin reduces gluconeogenesis -glucagon promotes gluconeogenesis

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21
Q

Why is sexual reproduction preferred over asexual reproduction for species that can achieve offspring through both?

A

sexual reproduction increases the likelihood of each individual offspring surviving

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22
Q

Mitotic spindles are composed of what structures?

A

Microtubules

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23
Q

Actin is composed of what structures?

A

Microfilaments

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24
Q

Which species do not have nuclei and do not need nuclear localization signals?

A

Bacteria & Archae

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25
How can blood be buffered by plasma proteins?
The amino acid residues in the protein may act as Bronsted acids or bases, reducing shift in pH
26
Analogous Structures
Same structure and function Ex. a wing of a bee and a wing of a bird
27
Homologous Structures
Different structures, similar function Ex. arm of a human and a flipper of a walrus
28
What three aspects help maintain the resting membrane potential of a neuron?
\*need to have an electrochemical gradient present in order to establish voltage difference that maintains membrane potential\* -outside cell has more Na+ and inside cell has more K+- 1. Passive transport: Potassium leak channels help ensure the passive transport of K+ out of the cell 2. ATP: provides energy to active transport pumps to transfer ions against their gradient 3. Membrane selective permeability: the membrane is more selective to K+ than Na+ ions
29
What are the three viable types of trisomies
-Trisomy 21 (Down Syndrome) -Trisomy 18 (Edward's Syndrome) -Trisomy 13 (Patau's Syndrome)
30
Eukaryotic Post-Transcriptional Modification
-occur on the mRNA -occur in the nucleus
31
Bacteria
- have no introns -prokaryotes that have a cell wall; viral budding cannot occur
32
Viral Budding
what allows viruses to leave the host cell
33
Chronic hyperglycemia results in what molecules in the urine?
Glucose and Ketone Bodies
34
RT-PCR
Reverse Transcriptase Polymerase Chain Reaction -measures RNA expression -cDNA is made by reverse transcribing RNA template
35
Southern Blot
\*\*DNA sequencing\*\* -allows you to visualize specific part of DNA of interest -after DNA is cleaved via enzymes, put through gel electrophoresis: separates based on SIZE and CHARGE
36
Gel Electrophoresis
37
Western Blot
Used to analyze \*PROTEINS\* -same process as Southern Blotting
38
Northern Blot
(RNA Blot) Used to study gene expression by isolating RNA, mRNA
39
Ectoderm
Skin, nervous tissue (including peripheral nervous system), adrenal medulla, epithelial lining of mouth and anus.
40
Mesoderm
Heart, kidney, spleen, circulatory system, muscle, bone, lymphatic system, wall of gut, gonads, adrenal cortex
41
Endoderm
Epithelial lining of digestive tract (other than mouth and anus), liver, pancreas, lungs
42
Characteristics of Cell Membranes
- fluid mosaic model - transmembrane proteins are able to freely move around in parallel in the membrane - hydrophilic heads with hydrophobic tails - transmembrane proteins are usually localized on lipid rafts that are high in cholesterol
43
Endosomal Pathway
endocytosis --\>vesicle --\> early endosome --\> late endosome --\> lysosome
44
Evolutionary relationship between species
- first to branch off: have least amount of genetic material in common because of the time in between that has accumulated mutations - last to branch off: has the most genetic material in common because just recently had a mutation that made it different
45
Peripheral Nervous System
- two branches: Sensory (afferent) Divison & Motor (efferent) Division 1. Sensory: somatic and visceral sensory nerve fibers transmit information to the CNS 2. Motor: motor nerve fibers transmit impulses from CNS to peripheral tissues 2a: Somatic Nervous System: VOLUNTARY motor nerve fibers that trasnsmit impulses from CNS to muscles 2b: Autonomic Nervous System: INVOLUNTARY nerve fibers that transmit information from CNS to cardiac smooth muscles and glands
46
Autonomic Nervous System
INVOLUNTARY (visceral motor) nerve fibers that transmit impusles from CNS to cardiac and smooth muscle glands. - Sympathetic Division: fight or flight; conveys impulses to cardiac muscle glands - Parasympathetic Division: "rest and digest"; conveys impulses to stomach and digestive system
47
Mast Cells
Immune cells in lungs covered in antibodies. They release inflammatory chemicals upon antigen binding to promote immune responses
48
Lysozyme
Enzyme able to attack the peptidoglycan walls of gram positive bacteria -tears, nasal cavity, saliva
49
Complement
Proteins that nonspecifically punch holes in the cell membrane of bacteria, making them osmotically unstable
50
Interferon
- Released by cell upon viral infection to block cellular and viral protein production - Decreases cell membrane permeability - upregulates MHC1 and MHC2 on cell surface to signal immune system - malaise, tiredness, muscle soreness, fever
51
Major Histocompatability Complex (MHC)
- binds to antigens and carries it to the cell surface where it can be recognized by other immune cells - Produced by virally infected cells via interferons - Endogenous Pathway: When MHC-1 is made by all cells, when foreign protein is presented to cell surface from inside cell, immune cells know that cell is infected - Exogenous Pathway: involves MHC-2 which is only produced by macrophages, dendritic cells, and some B-cells. Takes antigens from environment, processes inside cell, presents on surface.
52
Natural Killer Cells
Detect and destroy cells with downregulated MHC. Includes cancer cells and virally infected cells.
53
Neutrophils
Follow bacteria via chemotaxis and phagocytize them - dead neutrophils = pus - most populaous cell - NEUTRAL: because it will eat anything
54
Eosinophils
Release large amounts of histamine upon activation for inflammation THINK :Eosinophilic Asthma
55
Basophils
Produces large amoutns of histamine in response to allergens. Closely relateld to mast cells - less populous - have large, purple granules
56
Histamine
Causes inflammation by inducing vasodilation and increasing leakiness of blood vessels so additional immune cells can enter tissue -released by mast cells, eosinophils, basophils
57
Mucous Cells
Type of gastric gland in the stomach. Produce bicarbonate-rich mucus that protects the walls of the stomach from highly acidic and proteolytic environment
58
Cheif Cells
Gastric gland in the stomach. Secrets pepsinogen in the stomach (inactivated form of pepsin)
59
Parietal Cells
Secrete Hydrochloric Acid in the stomach to lower pH and cleave pepsinogen into pepsin -helps kill harmful bacteria and denature proteins
60
Pepsin
Enzyme whose precursor is pepsinogen (secreted by cheif cells) which is activated by HCl. -cleaves peptide bonds near aromatic amino acid
61
Gastrin
Secreted by G-cells in the pyloric section of the stomach. -induces parietal cells in the stomach to release more HCl and signals stomach to contract
62
Countercurrent Multiplier System
System in which Vasa Recta and Nephron flow in opposite directions, allowing more hypertonic blood to be exposed to the loop of Henle to allow for maximum water absorption
63
Loop of Henle
Descending Loop: only permeable to water, water leaves the loop creating a highly concentrated solution by the end of the loop Ascending Loop: only permeable to salts. Allows highly concentrated fluid to be reabsorbed by the vasa recta, decreases concentration by the time the fluid gets to the distal convoluted tubule.
64
Major waste products excreted in Urine:
DUMP the HUNK: H+, Urea, NH3, K+
65
Diluting Segment
Thicker portion of the ascending loop of the Loop of Henle -cells with more mitochondria because it is participating in more active transport of pushing salts out against their concentration gradient since fluid inside loop of Henle is more hypotonic compared to interstitium
66
Proximal Convoluted Tubule
- leads to Bowman's Capsule - Amino acid, salts, glucose, and Vitamins are reabsorbed into the Vasa Recta - 70% of filtered sodium is reabsorbed here - H+, K+, NH3 is all secreted here
67
Collecting Duct
Final concentration of urine is largely dependent on the permeability of the collecting duct - affected by ADH and Aldosterone to increase water absorption and concentrate urine output - water travels to vasa recta where it reenters blood stream
68
Red Fibers
Slow twitch fibers that have high mygloblin content and derive energy aerobically. -lots of mitochondria
69
White Fibers
- fast twitch fibers that have less myglobin - contract rapidly but fatigue quickly
70
Tropomyosin
Protein that spirals around actin in muscles, covers the myosin binding site
71
Myosin
Motor proteins in muscles. Binds to actin filaments in a cocked position with the ADP + Pi bound -only attaches to actin once Ca2+ binds to troponin, moving tropomyosin and exposes myosin binding site =After myosin-actin binding, ADP +Pi dissociate from myosin --\> causes power stroke --\> contracts sarcomere -ATP then binds to myosin, freeing it from actin, then is hydrolyzed to form ADP + Pi and put myosin back into cocked position
72
Tetanus
When muscle contractions do not get a break due to constant stimulation at high frequency

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