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BIOLOGY Flashcards

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1
Q

connective tissues often form the support structure for epithelial cells, often known as the ________

A

stroma

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2
Q

which kinds of nucleic acids could form the genome of a virus

A

all kinds - can be DNA or RNA, double or single stranded

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3
Q

which of the following is surrounded by a single membrane : lysosomes, nuclei, mitochondria, ribosomes

A

lysosomes

  • nuclei and mitochondria have a double membrane
  • ribosomes don’t have a membrane
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4
Q

prokaryotes have ribosomal subunits of _____ and ______ while eukaryotes have ribosomal subunits of ________ and ________

A

30S and 50S
40S and 60S

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5
Q

______ is the primary protein in microtubules and _______ is the primary protein in microfilaments

A

tubulin ; actin

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6
Q

what happens during the lytic cycle

A

the virus’s DNA takes control of the host cell’s genetic machinery and manufactures progeny
the host cell bursts (lyses) and releases virions capable of infecting other cells
- the outbreak stage

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7
Q

what happens during the lysogenic cycle

A

viral DNA is added to the host cell’s genome where it can remain dormant for days or years

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8
Q

what kinds of viruses have tail sheaths and tail fibers

A

bacteriophages - viruses that infect bacteria

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9
Q

what three methods of bacterial recombination can account for genetic variability

A

transformation, conjugation and transduction

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10
Q

what are F+ bacteria

A

F-positive bacteria that have a fertility factor in their plasmid
- allows it to form sex pilus for conjugation

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11
Q

prokaryotic organisms are always ______ while eukaryotic organisms can be _______

A

single celled ; uni or multicellular

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12
Q

describe the structure of the nucleus

A

surrounded by the nuclear membrane/envelope (a double membrane)
nuclear membrane has pores that allow for selective two-way exchange

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13
Q

what are histones

A

organizing proteins around which linear DNA is wound
- further wound into linear strands known as chromosomes

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14
Q

what is the function of the nucleolus

A

site of ribosomal RNA synthesis

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15
Q

what is the function of the outer membrane of the mitochondria

A

serves as a barrier between the cytosol and inner environment of the mitochondrion

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16
Q

what is the structure and function of the inner membrane of the mitochondria

A
  • arranged in numerous infoldings called cristae in order to increase surface area
  • contains molecules and enzymes necessary for the electron transport chain
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17
Q

the space between the inner and outer membranes of the mitochondria is called the _______ and the space inside the inner membrane is called the ______

A

inter-membrane space
mitochondrial matrix

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18
Q

what is cytoplasmic or extranuclear inheritance

A

the transmission of genetic material independent of the nucleus
- example: mitochondria can self-replicate

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19
Q

which organelles can be responsible for cell apoptosis

A

mitochondria and lysosomes

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20
Q

what is the function of lysosomes

A

membrane-bound structures containing hydrolytic enzymes that are capable of breaking down many different substrates

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21
Q

what is autolysis

A

the destruction of cells and tissues by their own enzymes, specifically those released by lysosomes

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22
Q

what is the function of endosomes

A

transport, package and sort cell material traveling to and from the membrane

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23
Q

what is an example of a kind of cell that has no organelles at all?

A

red blood cell

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24
Q

what is the function of the smooth endoplasmic reticulum

A

lipid synthesis, detoxification of drugs, transportation of proteins from rough endoplasmic reticulum to golgi

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25
Q

what is the function of the rough endoplasmic reticulum and how is it different from the smooth one

A
  • different because it is studded with ribosomes which help its function
  • mainly involved in protein synthesis as well as folding and sorting
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26
Q

materials from the endoplasmic reticulum are transported to the ______ in ______

A

golgi apparatus ; vesicles

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27
Q

what is the function of the golgi apparatus

A

modification and shipping of proteins/cellular products

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28
Q

what is the function of peroxisomes

A

contain hydrogen peroxide and break down long fatty acid chains via beta oxidation
- can also participate in the synthesis of phospholipids and contain some of the enzymes involved in the pentose phosphate pathway

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29
Q

what are the three components of the cytoskeleton

A

microtubules, microfilaments, and intermediate filaments

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30
Q

what are the functions of microfilaments

A
  • provide protection for the cell because actin filament bundles are resistant to compression and fracture
  • can also use ATP to generate force for movement by interacting with myosin (muscle contraction)
  • play a role in cytokinesis (division of materials between daughter cells) by forming the cleavage furrow
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31
Q

what is the structure of microfilaments

A

made up of solid polymerized rods of actin

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32
Q

what is the structure of microtubules

A

hollow polymers of tubulin proteins

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33
Q

what protein are thick filaments composed of

A

myosin

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34
Q

what are the functions of microtubules

A
  • provide the primary pathways along which motor proteins like kinesin and dynein carry vesicles
  • can make up motile structures like cilia and flagella
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35
Q

how are cilia and flagella different

A

cilia are primarily involved in movement of materials along surface of the cell (cilia in respiratory tract move mucus) while flagella are involved in the movement of the cell itself

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36
Q

what is the structure of eukaryotic organelles of motility

A

9+2 structure - nine pairs of microtubules forming an outer ring with 2 microtubules in the center

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37
Q

where are centrioles found

A

region of the cell called the centrosome

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38
Q

how are centrioles involved in mitosis

A

migrate to opposite poles of the dividing cell and organize the mitotic spindle
the microtubules coming from the centrioles attach to the chromosomes via complexes called kinetochores and pull them apart

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39
Q

what are intermediate filaments

A

a diverse group of filamentous proteins including keratin, desmin, vimentin, and lamins

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40
Q

what are the functions of intermediate filaments

A
  • involved in cell-cell adhesion
  • maintenance of overall cytoskeleton integrity
  • increase structural rigidity of cell because they can withstand large amounts of tension
  • anchor other organelles
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41
Q

how are centrioles structured

A

as nine triplets of microtubules with a hollow center

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42
Q

what are the four types of tissues

A

epithelial, connective, muscle, and nervous

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43
Q

what are the functions of epithelial cells

A
  • cover the body and line its cavities to protect against pathogen invasion and desiccation
  • can be involved in absorption, secretion, and sensation
  • different functions according to the organ in which they are found
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44
Q

what is the basement membrane

A

an underlying tissue of connective tissue that epithelial cells are tightly joined to in order to remain as one cohesive unit

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45
Q

parenchyma

A

functional parts of the organ
- mainly composed of epithelial cells

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46
Q

what does it mean that epithelial cells are polarized

A

one side faces a lumen and the other interacts with underlying blood vessels/structural cells

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47
Q

what are the three shapes of epithelial cells

A

cuboidal (cube-like), columnar (long and thin), and squamous (flat and scale-like)

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48
Q

simple epithelia vs stratified epithelia vs pseudostratified epithelia

A

simple - one layer of cells
stratified - multiple layers of cells
pseudostratified - appear to have multiple layers due to differences in cell height but actually just one

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49
Q

what are the functions of connective tissues

A
  • support the body
  • provide framework for epithelial cells to carry out their functions
  • produce and secrete materials such as collegen and elastin to form the extracellular matrix
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50
Q

epithelial cells contribute to the _______ of an organ while connective tissues contribute to the ________

A

parenchyma (functional part) ; stroma (supportive part)

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51
Q

what are some bacterial targets of antibiotics

A

the flagellum and the ribosome

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52
Q

spherical bacteria are known as ______, rod-shaped bacteria are known as ______, and spiral-shaped bacteria are known as ______

A

cocci ; bacilli ; spirilli

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53
Q

obligate aerobes

A

bacteria that require oxygen for metabolism

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54
Q

obligate anaerobes

A

bacteria that cannot survive in the presence of oxygen

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55
Q

facultative anaerobes

A

can use oxygen if its present but it’s not necessary

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56
Q

aerotolerant anaerobes

A

unable to use oxygen for metabolism but are not harmed by its presence

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57
Q

what is the envelope of prokaryotic cells

A

cell wall + inner cell membrane

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58
Q

what is the structure of gram-positive bacteria

A

cell walls consist of a thick layer of peptidoglycan

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59
Q

what is the structure of gram-negative bacteria

A

very thin cell walls that also contain peptidoglycan but a much smaller amount
- have outer membranes containing phospholipids and lipopolysaccharides

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60
Q

what aspects of gram-positive and negative bacteria cause an inflammatory response in humans

A

gram-positive - lipoteichoic acid
gram-negative - lipopolysaccharides

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61
Q

what does the antibiotic penicillin target

A

the enzyme (transpeptidase) that catalyzes the cross-linking of peptidoglycan

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62
Q

what is chemotaxis

A

ability of a cell to detect chemical stimuli and move toward or away from them

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63
Q

what are the three components of flagella

A

filament, basal body, hook

64
Q

T or F: plasmids are considered part of the genome of bacteria

A

F

65
Q

what are episomes

A

a subset of plasmids that are capable of integrating into the genome of the bacterium

66
Q

what is binary fission

A

asexual reproduction in bacteria that produces clone daughters

67
Q

what is transformation in bacteria

A

the integration of foreign genetic material into the host genome

68
Q

explain bacterial conjugation

A

form of sexual reproduction that involves two cells forming a conjugation bridge that facilitates the transfer of genetic material
- unidirectional transfer from donor male (F+) to recipient female (F-)
- the F- female then becomes an F+ and can go on to donate to others

69
Q

how is transduction different from other recombination processes

A

requires a vector - a virus that carries genetic material from one bacterium to another

70
Q

what are transposons

A

genetic elements capable of inserting and removing themselves from the genome

71
Q

what are the 4 phases of bacterial growth

A

lag (adapting to local conditions), exponential/log (rate of division increases after adaptation), stationary (reduction of resources slows reproduction), and death (depletion of environment, bacteria can no longer support themselves)

72
Q

the protein coat of a virus is called a _______ and it may be surrounded by an _______

A

capsid ; envelope

73
Q

T or F: enveloped viruses are easier to kill

A

T

74
Q

what is the name for viral progeny

A

virions

75
Q

what is the function of the tail sheath and fibers of bacteriophages

A

tail sheath acts as a syringe, injecting genetic material into the bacterium
tail fibers help the bacteriophage recognize and connect to the correct host cell

76
Q

single-stranded RNA viruses may be _____ or ______ sense

A

positive ; negative

77
Q

what are positive sense RNA viruses

A

single-stranded
- their genome can be directly translated to functional proteins by the ribosomes of the host cell

78
Q

what are negative sense RNA viruses

A

single-stranded
- the strand acts as a template for synthesis of a complementary strand which can then be used for protein synthesis
- must carry an RNA replicase to ensure the complementary strand is made

79
Q

what are retroviruses

A

enveloped, single-stranded RNA viruses where the virion contains two identical RNA molecules
- they carry an enzyme known as reverse transcriptase which synthesizes DNA from single-stranded RNA (allows it to integrate into the host cell genome which is why these are so difficult to treat)

80
Q

what is an example of a retrovirus

A

HIV

81
Q

what kind of viruses have to enter the nucleus in order to be transcribed

A

DNA viruses

82
Q

T or F: viral genomes have to be returned to their original form before re-packaging

A

T

83
Q

what are the three methods of progeny release for viruses

A
  1. cell death - viruses spill out
  2. lysis - cell bursts from being so full and viruses spill out (disadvantageous because viruses can’t reuse this cell)
  3. extrusion - leaves cell by fusing with plasma membrane
84
Q

what does it mean for a virus to be in a productive cycle

A

virus that leaves cell using extrusion - keeps host cell alive so it can be continually used

85
Q

viruses in the lytic phase are termed _______

A

virulent

86
Q

viruses in the lysogenic phase are termed ______

A

prophages/proviruses

87
Q

what are prions

A

infectious proteins that cause disease by triggering the misfolding of other proteins (usually the conversion of alpha helix to beta pleated sheet)

88
Q

what are viroids

A

small pathogens consisting of a very short circular single-stranded RNA that infect plants
- cause disease by silencing genes

89
Q

what is a viroid that affects humans

A

hepatitis D virus (harmless if not coinfected with hep B)

90
Q

what is interphase

A

the collective of G1, S, and G2 phases

91
Q

T or F: individual chromosomes are visible during interphase

A

F - they are in the less condensed form known as chromatin

92
Q

what happens in the G1 stage of mitosis

A

this is the presynthetic gap and, here, cells create organelles for energy and protein production while also increasing in size

93
Q

where are the restriction or check points in mitosis

A

between G1 and S and between G2 and M

94
Q

what happens in the S stage of mitosis

A

the cell replicates its genetic material so that each daughter cell will have identical copies

95
Q

what are sister chromatids

A

two identical chromatids bound together at the centromere (after synthesis stage)

96
Q

what happens in the G2 stage of mitosis

A

this is the postsynthetic gap and, here, the cell goes through a quality control checkpoint

97
Q

what is the G0 stage

A

an offshoot of G1 stage where the cell is simply carrying out its functions and not preparing for division

98
Q

what is the main protein in control of regulating mitotic checkpoints

A

p53

99
Q

what is the relationship between cyclins and cyclin-dependent kinases (CDKs)

A

-both responsible for the cell cycle
- CDKs require cyclins to be activated
- when CDK-cyclin complex is formed, this complex can then phosphorylate transcription factors

100
Q

what is one of the most common mutations found in cancer

A

mutation of the gene that produces p53, called TP53

101
Q

what happens in prophase

A
  • condensation of chromatin into chromosomes
  • nuclear membrane disappears
  • centriole pairs separate and go to opposite pairs of the cell
  • centrioles begin to form spindle fibers which attach to kinetochores of the chromosomes
102
Q

what happens in metaphase

A

the kinetochore and spindle fibers interact to align the chromosomes at the metaphase/equatorial plate (middle of the cell)

103
Q

what happens in anaphase

A
  • centromeres split so each chromatid has its own centromere and separates from its sister
  • sister chromatids pulled to opposite sides of the cell
104
Q

what happens in telophase

A
  • spindle apparatus disappears
  • nuclear membrane reforms and chromosomes uncoil
  • reverse of prophase
105
Q

what happens in cytokinesis

A

separation of the cytoplasm and organelles; division into two daughter cells

106
Q

which stage of mitosis has the lowest amount of DNA content and why

A

G1
- happens right after division and right before synthesis

107
Q

meiosis results in how many cells

A

up to four nonidentical sex cells

108
Q

Meiosis I results in _____________ being separated, generating _________ daughter cells; this is known as ____________

A

homologous chromosomes ; haploid ; reductional division

109
Q

Meiosis II results in ____________ being separated, generating ________ daughter cells; this is known as ____________

A

sister chromatids ; haploid (no change in ploidy) ; equational division

110
Q

explain the process of synapsis and when it occurs

A

happens during prophase 1 of meiosis and is when homologous chromosomes come together and intertwine
- each of these pairs is called a tetrad
- held together by a group of proteins called the synaptonemal complex

111
Q

explain the process of crossing over and when it happens

A
  • happens during prophase 1 of meiosis
  • chromosomes in a tetrad may break at the point of contact (called the chiasma) and exchange equivalent pieces of DNA
  • only occurs between homologous chromosomes and not sister chromatids
  • a way of genetic recombination
112
Q

where in the cell cycle can you see Mendel’s second law (of independent assortment)

A

prophase 1 of meiosis - crossing over

113
Q

where in the cell cycle can you see Mendel’s first law (of segregation)

A

anaphase 1 of meiosis - disjunction (separation of homologous chromosomes)

114
Q

what is disjunction

A

separation of homologous chromosomes in anaphase 1 of meiosis

115
Q

what is interkinesis

A

short rest period between cell divisions where chromosomes partially uncoil

116
Q

why are males called hemizygous

A

this is in respect to many of the genes on the X chromosome because they only have one copy

117
Q

what is the SRY gene

A

sex-determining region Y
- codes for a transcription factor that initiates testis differentiation and the formation of male gonads

118
Q

what are the two fundamental components of the testes

A

seminiferous tubules and interstitial cells of Leydig

119
Q

sperm are produced in the ________ where they are nourished by _________

A

seminiferous tubules ; Sertoli cells

120
Q

the cells of Leydig secrete ________

A

testosterone and other androgens

121
Q

what is the ductus deferens and what does it do

A

layer of muscle around the vas deferens that can raise and lower the testis to maintain the proper temperature for sperm development

122
Q

mnemonic for pathway of sperm through the male reproductive system

A

SEVEN UP

Seminiferous tubules
Epididymis
Vas deferens
Ejaculatory duct
Nothing
Urethra
Penis

123
Q

what do the seminal vesicles contribute to the sperm

A

fructose for nourishment

124
Q

what two things give sperm mildly alkaline properties

A

seminal vesicles and the prostate gland

125
Q

in spermatogenesis, four haploid sperm are formed from a

A

spermatogonium

126
Q

spermatogonium –> __________ (S stage) –> __________ (meiosis I) –> ____________ (meiosis II) –> __________ (maturation)

A

primary spermatocytes, secondary spermatocytes, spermatids, spermatozoa

127
Q

where are sensory and mechanoreceptors located in the skin

A

epidermis and dermis

128
Q

which processes regulate the body when temperature is above normal and how

A

vasodilation - widening of blood vessels ; relaxation of smooth muscle that surrounds the vessels

sweat - hypotonic solution secreted on the skin that causes cooling due to evaporation of water (endothermic process that absorbs heat from the body)

129
Q

which processes regulate the body when temperature is below normal and how

A

vasoconstriction - narrowing of blood vessels ; contraction of smooth muscle

shivering - generates heat through contraction of skeletal muscle

130
Q

what are the arrector pili muscles

A

muscles attached to hair follicles in the skin
- in cold environments, sympathetic signaling causes contraction of these muscles which causes piloerection (hair standing upright)

131
Q

which layer of the skin controls thermal insulation/regulation of temperature

A

hypodermis (lowest layer/subcutaneous layer)

132
Q

what are the 5 layers of the epidermis

A

stratum corneum, stratum lucidum, stratum granulosum, stratum spinosum, and stratum basale

133
Q

what happens in the stratum basale

A
  • deepest layer of the epidermis
  • consists of a single row of stem cells that continually divide
  • of the two daughter cells produced, one remains in the basal layer and the other differentiates into a mature keratinocyte
134
Q

what does the stratum corneum consist of

A
  • outermost layer of the epidermis
  • 20-30 layers of dead keratin-filled cells
  • functions as barrier protection (against pathogens, UV, water loss)
135
Q

what are Langerhans cells

A
  • dendritic immune cells found in the epidermis of the skin
  • recognize and ingest antigens ; then show these antigens to T cells activating the adaptive immune response
136
Q

what is thee difference between the adaptive vs innate immune response

A

the adaptive response is highly targeted to eliminate a specific pathogen whereas the innate response is generalized to attack any foreign substance

137
Q

what is the flow of the excretory system

A

the functional unit of the kidney is the nephron ; each kidney has about 1 million nephrons ; the nephrons eventually empty into the renal pelvis which narrows to form the ureter ; urine travels through the ureter to the bladder ; urine goes from bladder to urethra to out of the body

138
Q

what is a portal system

A

system consisting of two capillary beds in series through which blood must travel before returning to the heart

139
Q

what are the three major portal systems in the body

A
  1. kidney portal system : renal artery to loop of Henle
  2. hypophyseal portal system : connects hypothalamus and anterior pituitary
  3. hepatic portal system : connects gut tube and liver
140
Q

what are the two layers of the kidney

A

cortex (outermost layer) and medulla (sits within the cortex)

141
Q

explain the portal system of the kidney

A
  • the renal artery branches out, passes through the medulla, and enters the cortex as afferent arterioles
  • the capillary tufts from these afferent arterioles are glomeruli
  • after blood passes through a glomerulus, the efferent arterioles then form a second capillary bed
  • these capillaries surround the loop of Henle and are known as vasa recta
142
Q

describe the structure of the nephron

A
  • around the glomerulus is a cup-like structure known as Bowman’s capsule
  • Bowman’s capsule leads to a long tubules with many distinct areas : the proximal convoluted tubule, the descending and ascending limbs of the loop of Henle, distal convoluted tubule, and collecting duct
143
Q

the bladder has a muscular lining known as the _________

A

detrusor muscle

144
Q

the internal urethral sphincter consists of ________ muscle and is under _______ control

A

smooth ; involuntary (parasympathetic)

145
Q

the external urethral sphincter consists of _________ muscle and is under _______ control

A

skeletal ; voluntary

146
Q

what is the micturition reflex

A

when the bladder is full, stretch receptors cause parasympathetic neurons to fire which contracts the detrusor muscle –> this causes the internal sphincter to relax —> person then decides to relax external sphincter or not

147
Q

explain the trends of hydrostatic and oncotic pressure in the nephrons

A
  • hydrostatic pressure of glomerulus is much higher than that in Bowman’s space which causes fluid to move into the nephron
  • osmolarity of blood in glomerulus is higher than that of Bowman’s space so oncotic pressure opposes movement of fluid into Bowman’s space
  • hydrostatic pressure is much larger than oncotic so overall net flow is still from blood into nephron
148
Q

the movement of fluid into Bowman’s space is governed by

A

Starling forces

149
Q

filtration is movement of solutes from ________ to ________ at _________
secretion is movement of solutes from ________ to _________ at
reabsorption is the movement of solutes from _________ to _______

A

blood ; filtrate ; Bowman’s capsule
blood ; filtrate ; anywhere besides Bowman’s capsule
filtrate ; blood

150
Q

what is the function of the proximal convoluted tubule

A
  • site of bulk reabsorption of glucose, amino acids, soluble vitamins, salt, and water
  • site of secretion for hydrogen ions, potassium ions, ammonia, and urea
151
Q

what is the function of the descending limb of the loop of Henle

A
  • it’s permeable to water but not salt
  • as filtrate moves, water is reabsorbed
  • vasa recta and nephron flow in opposite directions which creates a countercurrent multiplier system that allows maximal reabsorption of water
152
Q

what is the function of the ascending limb of the loop of Henle

A
  • it’s permeable to salt but not water
  • passively and actively reabsorbs salt
  • the diluting segment is in the outer medulla
153
Q

what is the function of the distal convoluted tubule

A
  • it’s responsive to aldosterone and is a site of salt reabsorption and waste product excretion
  • similar to proximal tubule
154
Q

what is the function of the collecting duct

A
  • it’s responsive to both aldosterone and ADH and has variable permeability, which allows reabsorption of the right amount of water
155
Q

what is aldosterone and how does it affect the kidney

A
  • it’s a steroid hormone regulated by the renin-angiotensin - aldosterone system
  • increases sodium reabsorption in the distal convoluted tubule and collecting duct thereby increasing water reabsorption
  • increases blood volume and pressure but no change in blood osmolarity
156
Q

what is antidiuretic hormone (also known as vasopressin) and how does it affect the kidney

A
  • peptide hormone synthesized by the hypothalamus an released by the posterior pituitary
  • its release is stimulated by low blood volume and high blood osmolarity
  • increases permeability of collecting duct to water, increasing water reabsorption
  • results in increased blood volume and pressure and decreased blood osmolarity
157
Q

what is the bicarbonate buffer equation

A

CO2 (g) + H2O (l) <-> H2CO3 (aq) <-> H+ (aq) + HCO3- (aq)

MCAT (7 decks)

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