Brainscape's Knowledge GenomeTM

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


See full index

MCAT > Biology > Flashcards

Biology Flashcards

1
Q

What are eukaryotic cell features?

A
  • contains a true nucleus
  • phospholipid bilayer membrane compartmentalizes function
  • contains membrane bound organelles
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is the function of the nucleus? How is DNA organized?

A

Nucleus contains all genetic information

Linear DNA is wrapped around histones –> chromosome

Transcription occurs in the nucleus then exports RNA to cytoplasm through nuclear pores

Associated with centrioles

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

What is the function of the mitochondria? Structures? Evolution?

A

Generation of ATP

Structural components are an outer and inner membrane (convoluted for high SA) with a matrix

Thought to have evolved from prokaryotes b/c it does contain some of its own genes that replicate via binary fission

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

What is the function of the lysosome?

A

Contains hydrolytic enzymes to break stuff down and works with endosomes to transport

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

What is the function of the ER? Eukaryotic ribosome size?

A

Continuous with nuclear envelope

Rough ER: studded w/ ribosomes (protein translation)
Smooth ER: lipid synthesis and detoxification, transports to Golgi via vesicles

Ribosome 40S and 60S to form 80S combined

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

What is the function of the Golgi?

A

Post office of the cell, post-translational modifications occur here like localizing signals to cellular location or secretion

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

What is the function of the peroxisome?

A

Oxidative reactions like breakdown of fatty acids

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

What is the function of the cytoskeleton? What are its components?

A

Responsible for cell structure, shape, and transport

Microfilaments: actin! and responsible for cytokinesis

Intermediate filaments: keratin! cell adhesion, organelle anchoring

Microtubules: tubulin!
- transport pathway motor proteins (kinesin:
anterograde (away from cell body), dyenin: retrograde
(toward cell body))
- cell shape
- associated with centriole/centrosome/kinetochore for
anaphase

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

What is epithelial tissue?

A

Covers body and lines all cavities for protection with highly diverse function and multiple layers
- absorption, secretion, diffusion, filtration etc.
Ovaries are an example

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

What is connective tissue?

A

Bone, cartilage, tendon (muscle to bone), ligament (bone to bone), adipose tissue, blood

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

What are prokaryotic cell features? DNA?

A

Single celled organisms that contain no nucleus or membrane bound organelles

Transcription is done in the cytoplasm and ETC is done along the membrane

Circular DNA

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

What are the prokaryotic cell domains? Shape classifications?

A

Archaea and bacteria

Cocci (spherical), bacilli (rod), spirilli (spiral) describe cell shape

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

Aerobes vs. anaerobes?

A

Obligate aerobes: require oxygen for metabolism

Anaerobe: do no require oxygen to survive

Obligate anaerobe: cannot survive in oxygenate environments

Facultative anaerobe: can switch b/w using O and not using O

Aerotolerant anaerobe: tolerate O but doesn’t use

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

What is the structure of a prokaryotic cell? DNA? Ribosome?

A

Cell wall:

  • outer barrier of cell that surrounds membrane
  • responsible for structure
  • associated w/ peptidoglycan
  • gram-positive (purple, mostly peptidoglycan)
  • gram-negative (pink/red, less peptidoglycan

Flagella:
- responsible for bacterial movement

DNA Structure:

  • circular DNA
  • also contains a plasmid for non-essential DNA

30S and 50S ribosomes combine to form 70S ribosome

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

What is binary fission? What are three types of genetic recombination for prokaryotes?

A

Binary fission: asexual reproduction of prokaryotic circular chromosomes

Genetic recombination: responsible for increasing diversity and evolution

  • transformation: uptake from environment
  • transduction: bacteriophages
  • conjugation: bacterial-mating (sexual reproduction)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are viruses? Structure? Genome?

A

Are acellular obligate parasites (not alive and rely on host cell machinery) that are tiny and way smaller than bacteria (can’t see on light microscope)

Structure:
- protein coat/capsid: w/ genetic material inside and a
- tail sheath/fibers: to inject genetic material into cell or
dock with cell for endocytosis

Genome:
- positive sense RNA: directly translated into proteins
- negative sense RNA: needs to synthesize
complementary strand that is translated
- retrovirus: RNA –> DNA that integrates with host
genome

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

What is the viral life cycle? Lytic cycle? Lysogenic cycle?

A

1) infection
- virus binds to receptor on cell surface
- either injects genetic material or is endocy-tosed

2) translation and progeny generation
- replicates in cell by its specific mechanism

3) release
- cell death and lysis spills virus everywhere
- or leaves through extrusion through membrane

Lytic cycle: replicates quickly and degrades host genome until it fills cell with virions and it lyses

Lysogenic cycle: integrates with host genome then gets triggered into the lytic cycle

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

Prions vs. virioids?

A

Prions: infectious misfolded proteins that can cause other proteins to misfold and can lead to aggregates

Virioid: plant pathogen

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

What are the cell cycle phases? Checkpoints?

A

1) G0: nothing happening, cell just living
2) G1 (interphase): cell growth
3) G1/S checkpoint: restriction point where cell cycle will arrest until DNA is repaired
4) S (interphase): DNA replication
5) G2 (interphase): more cell growth
6) G2/M checkpoint: another checkpoint to ensure no DNA damage
7) M (mitosis) and cell division

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

Proto-oncogene vs. oncogene?

A

Proto-oncogene: normal

Oncogene: cancerous

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

What are the steps of mitosis? End result?

A

Mitosis is the asexual division of somatic cells and results in two identical diploid daughter cells

1) interphase: preparing for division, cell growth, nuclear membrane disappears
2) prophase: chromatin condenses to chromosomes, spindle forms
3) metaphase: chromosomes line up at metaphase plate
4) anaphase: sister chromatids are pulled apart
5) telophase/cytokinesis: spindle disappears, nuclear membrane reforms, cells are separated

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

What are the steps of meiosis? End result?

A

Meiosis is the sexual division of gametocytes and results in four non-identical haploid gametes

Meiosis I
1) prophase I:
- homologous chromosomes synapse
- crossover occurs b/w homologous chromosomes
resulting in recombination
- single crossover: one part of arm, double crossover:
two parts of arm
2) metaphase I:
- homologous chromosomes line up at metaphase
plate
3) anaphase I:
- homologous pairs separate into sister chromatids
4) telophase I:
- cells are now haploid and have two sister chromatids
- two daughter cells

Meiosis II: essentially the same as mitosis where sister chromatids are separated resulting in four haploid daughter cells

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

What is nondisjuction?

A

Occurs during anaphase when chromosomes fail to separate so one cell has extra chromosomes and the other cell is missing a chromosome

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

X vs. Y chromosome? Male/female?

A

Male: XY

Female: XX

Y chromosome carries the SRY for testis
One X chromosome on a female is inactivated, both replicate but one replicates last

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

What is the male reproductive anatomy?

A

S emineferous tubules:

  • sperm production (sertoli cells)
  • testosterone proudction (leydig cells)
  • located in the testes that are in the scrotum

E pididymis: sperm is stored here

V as deferens: sperm travels through here

Ejaculatory duct: sperm exits here

U rethra: sperm enters here to carry through penis

P enis: and out of the body

Sperm is nourished by seminal fluid = semen
Midpiece contains a lot of mitochondria for flagellal movement

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

What is the spermatogenesis process? When does it start?

A

Starts at puberty in the seminiferous tubules and produces cells of equal size

Spermatagonia –> primary spermatocyte –> secondary spermatocyte –> spermatozoa

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

What is the female reproductive anatomy?

A

Ovaries:
- produces estrogen (female characteristics) and
progesterone (endometrium stuff)
- ovulates eggs

Fallopian Tubes: cilia propels eggs forward into the…

Uterus: muscular cavity and site of fetal development

Cervix: lower end of uterus and connects to the vaginal canal

Vulva: collection of external anatomy

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

What is the oogenesis process? When does it start?

A

This whole process occurs prior to birth

Primary oocyte –> secondary oocyte –> ovum (uneven division, some have more cytoplasm than others)

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

What is the menstrual cycle?

A

1) folicular phase:
- sheds previous uterine lining
- increased FSH and LH and estrogen

2) ovulation:
- LH surge triggers ovulation

4) luteal phase:
- increased progesterone inhibits secretion of FSH, LH, and GnRH

5) menstruation:
- uterine lining sloughs off and GnRH is no longer
inhibited

OR

5) pregnancy:
- fertilization occurs, detected by hCG

6) menopause:
- results with loss of sensitivity to hormones causing ovarian atrophy

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

What are the three different types of cell junctions?

A

Desmosome: anchors cytoskeleton

Gap junction: cell-cell communication

Tight junction: direct connection, no leakage

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

What are the early developmental stages of a fetus?

A

Fertilization:
- occurs in the ampulla: wides part of fallopian tube
- sperm penetrates into egg forming a unicellular
zygote
- dizygotic/fraternal: two eggs by two sperm
- monozygotic/identical: one zygote splits into two

Cleavage:
- occurs during travel from fallopian tube to uterus
- undergoes rapid cell division (now considered an
embryo)

Blastulation:

  • after division embryo is a mass of cells: morula
  • morula develops into a hollow ball of cells: blastocyst

Implantation:

  • in endometrium of uterus
  • now connected to the placenta via umbilical cord

Gastrulation:

  • germ layer formation
  • selective transcription is responsible for differentiation

Neuralation:

  • neural tube: CNS
  • neural crest: PNS
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

What are the different germ layers?

A

ectoderm: skin and nervous system, adrenal medulla
mesoderm: circulatory, muscoskeletal, and excretory system (kidney here), adrenal cortex
endoderm: lining of internal organs

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

What are features of fetal circulation? Affinity? Arteries/veins?

A

Fetal hemoglobin has higher affinity for oxygen than adult hemoglobin

Umbilical artery: flows away from fetal heart and towards placenta (deoxygenated)
Umbilical vein: flows towards fetal heart from placenta (oxygenated)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

Undifferentiated vs. totipotent vs. pluripotent vs. multipotent cells?

A

Undifferentiated: stem cells (self-renewal) have ability to differentiate into any cell

Totipotent: can differentiate into any cell type

Pluripotent: can differentiate into cells of any germ layer

Multipotent: can differentiate into cells of one germ layer

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

What are the three kinds of cell-cell signals?

A

Autocrine: act on same cell it was secreted from

Paracrine: acts of cells in local area

Endocrine: hormones travel through blood to distant tissue

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

What tissues types are regenerative?

A

Liver

Kidney to a certain degree

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

What are telomeres?

A

Highly repetitive sequences at the end of DNA that shorten with every round of replication

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

What is the function of a neuron? Structure?

A

Transmit electrical impulses then translated to chemical signals

Dendrites: receive incoming signals

Cell body/soma: houses nucleus

Axon hillock: integrates signals and site of action potential

Axon/myelin: propagates signals and insulates for better conduction (CNS: oligodendrocyte, PNS: schwann cells)

Synaptic cleft: area b/w pre/post synaptic neuron where neurotransmitters diffuse across

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

What is the function of other nervous system cells? Astrocyte? Ependymal? Microglia?

A

Astrocyte: maintains blood-brain barrier

Ependymal: maintains CSF

Microglia: immune system for the nervous system

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

What is the resting potential?

A

A negative potential difference (inside is negative, outside is positive) Na on the inside, K on the outside

Na/K ATPase establishes the equilibrium and leak channels maintain it

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

What is an action potential, steps?

A

An all or nothing impulse (when reaches threshold potential) starting from the axon hillock sent down axon and to synapse

Excitatory impulse causes voltage gated channels

1) increased permeability to Na, so Na channels open and influx (causes depolarization)
2) Na channels inactivate and K channels open
3) K efflux and repolarization
4) K stays open open too long so hyperpolarizes (refractory period: absolute is no firing, relative is firing if big stimulation beyond previous)
5) Na/K ATPase reequilibrates

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

What is the affect of length and area on conduction?

A

Increased length = increased resistance = decreased conduction

Increased area = decreased resistance = increased conduction

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

How are neurotransmitters released into the synapse after an action potential? How are they cleared?

A

Action potential causes the release of calcium which triggers exocytosis of neurotransmitter filled vesicles, neurotransmitters diffuse across synapse and bind to receptors

Neurotransmitters can be cleared by reuptake, enzymatic breakdown, or diffusion out of the synapse

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

What is the nervous system organization?

A

Nervous system is divided into the CNS and PNS

CNS is divided into the brain and spinal cord
PNS is divided into autonomic and somatic branches

Somatic branch is responsible for sensory and motor functions (voluntary)
Autonomic (involuntary) branch is divided into sympathetic (fight/flight) and parasympathetic (rest/digest)

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

Sensory vs. motor vs. interneurons?

A

Sensory neurons are also afferent neurons and send signals from receptors to the spinal cord and brain

Motor neurons are also efferent neurons and send signals from the brain and spinal cord to muscles/glands

Interneurons are the most abundant and connect all neurons

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

White matter vs. grey matter?

A

White matter: myelinated

Grey matter: cell body/unmyelinated parts

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

What are the vertebral divisions of the spinal cord?

A

Brain –> brain stem –> cervical –> thoracic –> lumbar –> sacral

Protected by the vertebral column
White matter outside, grey matter inside
Cell body in the DRG

48
Q

What is the fight/flight response?

A

Increased HR, BG, bronchodilation, vasoconstriction, pupillary dilation

49
Q

What is the reflex arc?

A

Happens at the level of the spinal cord instead of impulses traveling all the way to the brain

Like the knee jerk

50
Q

How does the endocrine system work? Endocrine vs. exocrine glands?

A

Endocrine glands secrete hormones into the bloodstream that then travel to distant tissue where they bind to receptors inducing a change

Endocrine gland: secrete directly into bloodstream (ductless)
Exocrine gland: secrete into a duct first

51
Q

Peptide vs. steroid hormones?

A

Peptide:
- amino acids
- packaged into vesicles and released by exocytosis
- polar/charged so cannot diffuse through membrane
so bind extracellular receptors and triggers a second
messenger/signal cascade
- b/c they are polar they are soluble in bloodstream
- rapid/short lived affect

Steroid:
- cholesterol derivative
- non-polar so can diffuse through membrane so bind
intracellular receptors
- affect comes by altering transcription of particular
genes
- b/c they are non-polar they are not water soluble so
require a carrier in bloodstream
- slow/long-lived affect

52
Q

What are amino acid derivative hormones?

A

tyrosine derivatives

thyroid hormones, epi/norepi (catecholamines), melatonin

53
Q

Direct vs. tropic hormones?

A

Direct hormones act directly on target tissue versus tropic hormones act through an intermediary hormone (hypothalamus hormones)

54
Q

What is the hypothalamus? Location? Mechanism of action?

A

Function: serves as link b/w nervous and endocrine system by regulating pituitary gland via tropic hormones

Location: in forebrain above pituitary and below thalamus

Action: paracrine release into portal system that links pituitary glands

55
Q

How is the posterior pituitary connected to the hypothalamus?

A

Connected via neurons to the hypothalamus

Oxytocin and ADH/vasopressin (posterior pituitary hormones) are synthesized in the hypothalamus but secreted by the posterior pituitary

56
Q

Where are the lungs located? What is the pathway of air into the lungs?

A

Lungs are located in the thoracic cavity are surrounded by pleura in the pleural space

1) air enters through the nares where it is filtered by mucous membranes and hair
2) then travels into the pharynx (air and food), over the epiglottis and into the larynx (air only)
3) then travels down the trachea and into bronchi –> bronchioles –> alveoli where capillaries area

Lungs can excrete water by humidifying air!

57
Q

What is the role of surfactant around the alveoli?

A

Surfactant reduces surface tension and prevents alveoli from collapsing

58
Q

Inhalation vs. exhalation process?

A

Inhalation
- diaphragm contracts to expand thoracic cavity
- that causes increased volume so decreased pressure
- that negative pressure differential b/w lungs and
atmosphere forces air in (NEGATIVE PRESSURE
VENTILATION)

Exhalation

  • diaphragm relaxes
  • lungs decrease in volume so pressure increases
  • that forces air out
59
Q

Total lung capacity? Residual volume? Vital capacity? Tidal volume? Expiratory reserve volume? Inspiratory reserve volume?

A

Total lung capacity: max volume of air in lungs

Residual volume: minimum volume of air in lungs

Vital capacity: difference b/w TLC and RV

Tidal volume: volume of air in a normal breath

ERV: volume of additional air that can forcibly exhaled after normal breath

IRV: volume of additional air that can be forcibly inhaled after normal breath

60
Q

How is breathing regulated?

A

Chemoreceptors sensitive to CO2 concentration and pH buffering

CO2 + H2O <> H2CO3 <> HCO3- + H+

H2CO3 = carbonic acid
HCO3 = bicarbonate
61
Q

What are the four functions of the respiratory system?

A

1) gas exchange
2) thermoregulation
3) immune function
4) pH control

62
Q

What is the immune function of the respiratory system?

A

Nasal cavity hairs trap pathogens and contain lysozymes that break down peptidoglycan (bacteria)

Mucus lines airways and can trap pathogens for expulsion or swallowing to digestion

Alveoli contains macrophages

63
Q

What is the pathway of blood through the cardiovascular system?

A

1) deoxygenated blood flows through the SVC and IVC into the RA
2) RA fills into the RV via the tricuspid AV valve
3) RV pumps blood to lungs via pulmonary artery and through semilunar valve
4) blood oxygenates in the lungs and returns via pulmonary vein to LA
5) LA fills into LV via bicuspid/mitral/AV valve
6) LV pumps blood to aorta through semilunar aortic valve

R side is pulmonary circulation
L side is system circulation

64
Q

What is the electrical conduction pathway of the heart?

A

1) starts at the SA node in the RA
2) depolarization causes both atria to contract simultaneously
3) signal reaches the AV node where it is delayed to allow ventricles to fill completely
4) AV node signal travels down the bundles of His and Purkinjie fibers that distributes signal to ventricles
- intercalated discs have gap junctions for coordinated contraction

Vagus nerve supplies parasympathetic signal

65
Q

What is systole vs. diastole in contraction? What is cardiac output equation?

A

Systole: ventricular contraction / closing of AV valves to pump out blood

Diastole: ventricular filling / closing of semilunar valves

BP is systole / diastole

CO = HR⋅SV

66
Q

Arteries vs. arterioles vs. capillaries vs. venules vs. veins? What are portal systems?

A

Blood flow travels arteries –> arterioles –> capillaries –> venules –> veins

Arteries: pumps blood away from heart, is highly muscular and elastic so has high resistance and high pressure to overcome

Arterioles: connect arteries and capillaries

Capillaries: single endothelial cell layer makes for easy diffusion to perfuse tissues (most area so least resistance)

Venules: connect capillaries to veins

Veins:
   - lowest pressure
   - returns blood to the heart
   - less muscular and elastic so can accommodate more 
     volume
   - valves prevent back flow
   - surrounded by skeletal muscle that supplies force on 
     movement to push blood to heart

Portal systems: blood travels through two capillary beds instead of just one before returning to heart (liver, hypothalamus, kidney)

67
Q

What is the composition of blood? Different cell types?

A

Liquid/plasma (with nutrients, salts, gases, hormones, proteins)

Cells
- erythrocytes (RBC’s): oxygen transport from
hemoglobin, lack organelles (nucleus, mitochondria
etc.) so there’s room for hemoglobin

  • leukocytes (WBC’s): granulocytes and agranulocytes
  • thrombocytes (platelets): blood clotting

Cells are synthesized from hematopoetic stem cells in bone marrow

68
Q

What are blood antigens? Allelic dominance? Rh factor

A

Blood antigens are surface proteins expressed on RBC’s that serve as targets for the immune system

A & B: co-dominant
O: recessive
O is universal donor and AB is universal recipient

Rh factor is another surface protein where (+) is dominant to (-), plays an important role maternal-fetal circulation as during birth that blood can mix and trigger an immune response

69
Q

Oxygen vs. carbon dioxide carried in blood?

A

Oxygen is carried by hemoglobin, a four subunit, cooperative binding protein)

Carbon dioxide is transported in blood as bicarbonate

70
Q

In oxygenation graph (partial pressure, pH) what does a left and right shift mean?

A

Left shift = high affinity

Right shift = low affinity (dumps oxygen into tissues)

71
Q

What is hydrostatic vs. osmotic pressure?

A

Hydrostatic: same as blood pressure, pushes fluid out of vessels

Osmotic: results from solute concentrations, pulls fluid into vessels

72
Q

Innate vs. adaptive immune system?

A

Innate: non-specific, always active against infections but doesn’t target specific pathogens

Adaptive: specific, targets a specific pathogen

  • humoral: antibodies
  • cytotoxic cell-mediated: t-cell destruction
73
Q

What is the function of the bone marrow? Spleen? Thymus? Lymph nodes in the immune system?

A

Bone marrow: produces erythrocytes, thrombocytes, leukocytes (WBC’s) via hematopoesis

Spleen: storage of B cells/antibodies

Thymus: responsible for T-cell development that is involved in cell-mediated immunity (adaptive/humoral)

Lymph nodes: where immune cells start attack from

74
Q

What’s the function of the skin, respiratory system, GI tract as non-cellular and non-specific defense?

A

Skin: acts as a physical barrier to pathogens

Respiratory system: pathogens can be trapped and expelled or digested

GI tract: stomach acid can kill most pathogens, also is populated by gut microbiota which prevents pathogen colonization

75
Q

What’s the function of macrophages, natural killer cells, and granulocytes as cellular and non-specific defense?

A

Macrophages:

1) phagocytizes (eats) invader via endocytosis
2) digests invader w/ enzymes
3) surface antigen presentation for adaptive immune system recognition
4) cytokine release

Natural Killer Cell: initiates apoptosis of infected cells

Granulocytes:

  • neutrophils: phagocytic
  • eosinophils: histamine
  • basophils: mast cells
76
Q

What is humoral immunity? What cell produces antibodies? Antibody structure? Antibody function?

A

Associated with antibodies that are produced by B-cells in the bone marrow

Antibodies are Y-shaped with the tip being the variable region (antibody binding area because it’s specific)

Antibodies attract macrophages, clump pathogen together, and block their ability to invade tissues

77
Q

What is cytotoxic immunity? What structure develops T-cells? What are the different types of t-cells?

A

T-cells are synthesized in the thymus

helper t cells: coordinate and recruit other immune cells

cytotoxic t-cells: kill infected cells

suppressor/regulatory t-cells: dampen immune response after infection is gone

memory t-cells: for next infection

78
Q

What is autoimmunity?

A

Normally self-recognizing (to body’s own antigens) immune cells are destroyed

But when the immune system fails to recognize self-antigens it attacks them as if they are foreign particle/pathogen

79
Q

Active vs. passive immunization?

A

Active: immune system is stimulated to produce antibodies by injection of weakened or killed antigens (vaccine) note for vaccine that it should not target a general function or it will be toxic, target something unique to pathogen so it affects pathogen only

Passive: a transfer of antibodies to individual (think maternal/fetal)

80
Q

What is the function of the lymphatic system?

A

Circulates lymphatic fluid
Associated with immune system in pathogen exposure
Fluid distribution
Fat transport

Lymph ducts drain into veins! and interstitial fluid is b/w lymph capillaries and veins

81
Q

Mechanical vs. chemical digestion?

A

Mechanical: physical breaking of large particles into smaller particles

Chemical: enzymatic cleavage of chemical bonds

82
Q

What is the pathway of food through the GI system?

A

1) oral cavity: chewing and salivary lipase
2) pharynx: which directs food to epiglottis and into
3) esophagus: connects pharynx with stomach, food moves down through peristalsis and past sphincter
4) stomach: then through pyloric sphincter to..
5) small intestine
6) large intestine
7) rectum

83
Q

What is the role of the stomach in digestion? pH environment? Enzymes?

A

Highly acidic environment with pepsin used to digest food

Stomach is also protected by a thick mucus lining to prevent autodigestion

84
Q

What is the role of the small intestine? pH environment? Enzymes? What are its parts? How does nutrient absorption work?

A

Basic environment with trypsin to digest but is mostly for nutrient absorption

Duodenum: chemical digestion
Jejunum: absorption
Ileum: absorption

Villi and microvilli increase surface area of epithelial cells that are connected to capillaries

85
Q

What is bile? Role in digestion? What is bilirubin?

A

Bile is a cholesterol derivative

It has hydrophobic and hydrophilic regions so emulsifies fats and cholesterol into micelles so they are water-soluble

Bilirubin is a bile pigment that is processed and excreted by liver also is a hemoglobin byproduct

86
Q

What is the role of the pancreas in digestion?

A

It synthesizes and releases many digestive enzymes directly to the small intestine
- amylase, peptidase, lipase

87
Q

What is the role of the liver?

A

Produces bile to store in the gallbladder or secrete directly to small intestine

Also processes blood from the abdomen for detoxification

Produces albumin (blood carrier protein) and clotting factors

Is also involved in sugar and fat storage (so regulates BG levels and oncotic pressure)

88
Q

What is the role of the gallbladder?

A

It functions for bile storage

The common bile duct connects the liver, gallbladder, and small intestine

89
Q

What is the role of the large intestine? Parts?

A

Functions for water reabsorption

Consists of the cecum, colon, and rectum

90
Q

What is the first step in nephron function?

A

Filtration
- blood from the glomerulus is filtered into Bowman’s
capsule
- that occurs because hydrostatic pressure in the
glomerulus is high
- no proteins or cells should be in filtrate

91
Q

What is the pathway through the nephron? Where are the structures located?

A

Proximal convoluted tubule

  • filtrate enters here after filtration
  • amino acids, glucose, vitamins, salts are reabsorbed
  • H+, urea, NH3, K+ is secreted into filtrate

Descending loop of Henle
- only permeable to water moving out

Ascending loop of Henle
- only permeable to salts moving out

Distal convoluted tubule

  • More reabsorption of salts and water
  • More secretion of H+, K+, and NH3

Collecting duct
- concentrates urine through water reabsorption

Tubules are located in the cortex
Loops and collecting duct are located in the outer medulla (upper), inner medulla (bottom)

92
Q

What are the two main hormones that regulate blood pressure? Mechanism?

A

Aldosterone: secreted by the adrenal cortex and acts on the DCT and collecting duct

  • reabsorb Na+ so water follows
  • K+ secretion
  • responds to low BP

ADH/vasopressin: secreted by the posterior pituitary and acts on the collecting duct

  • directly reabsorb more water via aquaporins
  • responds to high plasma osmolarity
93
Q

What are the layers of the skin?

A

Epidermis

  • outermost layer
  • merkel discs: respond to light touch
  • innervated by nerves

Dermis

  • middle layer
  • meisner corpuscle: respond to vibration + pressure
  • innervated by nerves

Hypodermis
- inner layer of connective tissue

94
Q

How does thermoregulation through the skin work?

A

Sweating
- evaporation of water (sweat) absorbs body heat for
cooling
- so vasodilation for more evaporative cooling

Can excrete water!

95
Q

Skeletal muscle vs. smooth muscle vs. cardiac muscle? In terms of voluntary, nucleated, striated?

A 
Skeletal muscle:
   - voluntary (somatic NS)
   - striated (actin and myosin arranged into sarcomeres)
   - troponin is involved
   - multinucleated
Slow twitch:
   - aerobic (oxidative)
   - high myoglobin and mitochondria
Fast twitch:
   - anaerobic (non-oxidative, so glycolysis only instead)
   - less myoglobin and mitochondria

Smooth muscle:

  • involuntary (autonomic NS)
  • not striated
  • mononucleated

Cardiac muscle

  • involuntary (autonomic NS)
  • striated
  • troponin involved
  • mononucleated
  • intercalated discs w/ gap junctions
96
Q

What is the sarcomere?

A

The contractile unit of muscle made of up of a thick filament: myosin, and a thin filament: actin, troponin, tropomyosin

97
Q

What is the muscle contraction cycle? MEPP, powerstroke? How does relaxation occur?

A

MEPP:

1) motor neuron sends signal to muscle via NMJ
2) acetylcholine is released into synapse and binds to receptors on sarcolema causing depolarization across t-tubules
3) signal reaches SR and Ca is released
4) Ca binds to troponin causing tropomyosin to shift revealing the myosin binding site on actin

Powerstroke:

1) Hydrolysis of ATP bound to myosin to ADP + Pi recocks myosin head
2) Myosin binds to actin
3) ADP + Pi is released and powerstroke occurs
4) ATP binds to myosin detaching it from actin

Relaxation:

1) acetylcholine is degraded
2) sarcolema repolarizes
3) Ca release ceased and reuptake occurs
4) myosin binding sites re-covered

98
Q

What is tetanus?

A

When frequent muscle contractions occur so there is no muscle relaxation

99
Q

Tendon vs. ligament?

A

Tendon: muscle to bone

Ligament: bone to bone

100
Q

Osteoclast vs. osteoblast?

A

Osteoclasts chew bone and releases calcium

Osteoblasts build bone and uses calcium

101
Q

What is the growth plate?

A

Area filled with mitotic cells that contribute to growth but past puberty the growth plates are closed

102
Q

Genotype vs. phenotype?

A

Genotype: genetic combination of alleles

Phenotype: observable traits

103
Q

Complete dominance vs. co-dominance vs. incomplete dominance?

A

Complete dominance: normal, one dominant and one recessive allele where the dominant masks the recessive

Co-dominance: both alleles are expressed simultaneously

Incomplete dominance: express a mixture of both alleles

104
Q

Penetrance vs. expressivity?

A

Penetrance: the proportion of population w/ a given genotype who actually express the phenotype

Expressivity: different manifestations of the same genotype across population (think diseases)

105
Q

What is the key factor in evolution and adaptation that precedes it?

A

Diversity and variation also that evolution and adaptation is a population-level affect

106
Q

Point mutation vs. frame shift mutation?

A

Point mutation: one nucleotide swap for another
- silent: no effect on final protein b/c of degeneracy/3rd
pair wobble
- missense: one amino acid substitution in final protein
- nonsense: results in a premature stop codon (UAA,
UGA, UAG)

Frameshift mutation: an insertion or deletion of a nucleotide results in a shift of the three codon reading frame

107
Q

Genetic leakage vs. genetic drift?

A

Leakage: gene flow b/w species that can result in hybrid offspring

Drift:
- changes in composition of gene pool due to chance
- these changes will be more pronounced and have
greater effect in smaller populations
- founder effect: small population finds itself in isolation
and inbreeding occurs (which increases likelihood for
recessive disease in offspring)
- generally causes a reduction in genetic diversity so
decreased fitness

108
Q

What is important to know about x-linked diseases? mitochondrial diseases?

A

X-linked diseases are much more common in males b/c they are XY (so any recessive disease will do it)

Mitochondrial/cytoplasmic diseases exhibit maternal transmission

109
Q

What is the Hardy Weinberg equilibrium equation? Assumptions?

A

p^2 + 2pq + q^2 = 1 and p + q = 1

p^2 = homozygous dominant
2pq = heterozygous dominant
q^2 = homozygous recessive

1) large population
2) no mutations
3) random mating
4) no migration
5) genes are equal

110
Q

What is natural selection?

A

Organisms produce offspring and some chance variations w/ in individuals may be heritable, those individuals w/ more favorable variations are more likely to survive and reproduce

POPULATIONS EVOLVE NOT INDIVIDUALS

111
Q

Stabilizing vs. directional vs. disruptive selection?

A

Stabilizing: selection towards the middle

Directional: selection towards an extreme

Disruptive: selection away from the middle and for two extremes (separate)

112
Q

What is speciation?

A

Formation of new species through evolution

113
Q

Divergent vs. parallel vs. convergent evolution?

A

Divergent: independent development of dissimilar characteristics in two or more lineages sharing a common ancestor (finches) / adaptive radiation

Parallel: related species evolve in similar ways for a long period of time

Convergent: independent development of similar characteristics in two or more lineages not sharing a common ancestor (dolphins/sharks)

114
Q

Analogous vs. homologous structure?

A

Analogous: structures with same function

Homologous: structures with different function

115
Q

What is an imprinted gene?

A

Genes expressed in parents in a specific manner

116
Q

How to analyze a pedigree?

A

Male = square Female = circle Highlighted = affected

1) determine if sex-linked or autosomal
- if x-linked recessive or y-linked it will be in males only

2) determine dominant or recessive
- dominant: appears in every generation, and the union
of two affected can have unaffected offspring
- recessive: skips generations, union of two unaffected
can have affected offspring

MCAT (7 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions