Brainscape's Knowledge GenomeTM

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


See full index

MCDB 1A > Clegg > Flashcards

Clegg Flashcards

1
Q

What did Robert Hooke do?

A

used a microscope to look at cells from a piece of cork, observed the cell walls of a dead cork oak

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

What did Antoni Van Leeuwenhoek?

A

considered the father of microbiology, first person to see bacteria and sperm cells
called them animalcules

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

What did Louis Pasteur do?

A
  • came up with cell theory: everything is made out of cells
  • crucial experiment: can life arise spontaneously of must it come from previous life?
  • found that all life comes from preexisting life
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

what is Pasteurization

A

heating beer and wine kills most of the bacteria that causes spoilage

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

What did alexander flemming do?

A
  • left plate out, grew penicillium mold, bacteria didn’t grow around it
  • discovered penicillin
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What does penicillin do to bacteria?

A

it kills bacteria by inhibiting the synthesis of the bacterial peptidoglycan walls, inhibits the enzyme transpeptidase

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

What did Banting and Best do?

A
  • removed the pancreas from dog, observed high blood sugar
  • ground up pancreas, inserted into another dog, blood glucose went down
  • purified insulin, miracle drug for diabetes
  • cloned gene and produced human insulin in E. coli
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Who is Henrietta Lacks?

A
  • cells from her cervical cancer were the first human cells to be grown in culture
  • studies show how cancer cells divide have led to the discover of drugs to fight cancer
  • HeLa cells
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Who is Rob Sinshiemer

A

father of the human genome project

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

What did Hans Spemann do

A
  • gastrulation generates multiple tissues
  • bisected eggs
  • found that cytoplasmic factors in the gray crescent are necessary for gastrulation and normal development
  • cytoplasmic factors = proteins and mRNAS
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is progeria

A

caused by mutations in Lamin-A

  • rare disease of premature aging
  • collapsed nucleus
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

diabetes melitus

A

-high blood sugar, weakness, lethargy, loss of weight
-Type 1 (juvinile) lack of the protein insulin- usually an autoimmune attack on the beta cells of the pancreas
Type 2: lack of insulin responsiveness - seen in adults

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

Tay-Sachs disease

A
  • common genetic lysosomal storage disease
  • lysosomes cannot break down certain glycolipids caused by mutation
  • glycolypids are toxic to brain cells
  • blindness, dementia, death by age 3
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

retinoblastoma

A

misregulation of cyclin/CDKs

  • caused by loss of a function mutation in the retinoblastoma protein (RB)
  • transcription factor, usually inhibits G1-S restriction pt
  • continuous cell cycle, tumor growth
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Down’s syndrome

A

an example of aneuploidy

  • trisome of chromosome 21
  • cranialfacial abnormalities, decrease number of neurons, predisposition to Alzheimer’s, leukemia, heart defects
  • caused by nondisjunction of homologous chromosomes in meiosis I
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

oncogenes

A

when mutated can cause cancer

  • gain of function mutation
  • mutant always active EGD receptor = cancer
  • mutant always active c-myc = cancer
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

blindness

A

mutation in the NADH dehydrogenase = blindness due to death of retinal cells

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

hypocholesterolmia

A
  • defects in the regulated uptake of the LDL particles
  • buildup of cholesetrol in plasma
  • Atherosclerosis - deposition of cholesterol on artery walls
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

familial hypocholestrolmia

A
  • absence of a function of LDL receptors prevents cholestrol from entering the cells and it accumulates in the blood
  • patches of yellow cholesterol around eyes, form of lumps on hands
  • heart disease at an early age
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

why are cells small

A

-rates of diffusion: governed by the size of the molecule, temperature, and size of the concentration gradient

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

collagen proteins are

A

found throughout the body, most abundant protein at 25%

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

largest organ in our body

A

skin - 9 lbs and 22 sq ft

-epidermis - held together by junctions

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

prokaryotes

A

always unicellular, can have varied shapes

  • often come together to form biofilms
  • certain parts of the world, many people die bc of prokaryotic diseases
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

structure of prokaryotes

A
  • all have plasma membrane
  • some have cell wall - rigid peptidoglycan
  • DNA free in the cytoplasm, localized in nucleoid
  • no membrane bound organelles
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

some prokaryotes have flagella, which are

A

long, whiplike projections that spin at the base to propel bacteria

  • flagellar motor spans entire membrane
  • counterclockwise rotation = forward
  • clockwise = tumbling
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

some prokaryotes have pili, which are

A

short hollow thread like structure from surface

  • helps bacteria adhere to each other/various spaced
  • builds bridges between two bacterial cells
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

what happens during bacterial sex

A

conjugation

  • plasmids: small circular DNA that encodes genes
  • transfers copied gene to other bacteria through pili during replication
  • led to gene coding and biotech
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

periplasmic space

A

outer membrane and inner membrane space, filled with the peptidoglycan cell wall

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

Eukaryotes have defining characteristics

A
  • can be unicellular (yeast, protists) or multicellular
  • contains membrane bound nucleus, contains most DNA
  • 10-100 times larger
  • complex organized cytoplasm, organelles, cytoskeleton & endomembrane
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

what is a nuclear envelope?

A
  • double membrane that binds a the nucleus
  • consists of inner and outer nuclear membrane
  • contiguous with ER, part of endomembrane system
  • has proteins localized on ONM and INM
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

The nucleus

A
  • largest organelle
  • contains chromosomes, DNA
  • supported by the nuclear lamina
  • has pores to regulate traffic in/out of nucleus
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

Nucleolus

A

contains ribosomal genes - where ribosomes are made

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

nuclear lamina

A
  • meshwork of cytoskelton inside near envelope
  • protein polymer - intermediate filament
  • monomers called lamin A,B,C
  • prevents compression of nucleus
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

nuclear pore complex

A
  • resides in between the folds of nuclear envelope
  • multicomponenet machine forms channels that allow passage of macromolecules
  • mRNA bound proteins go out
  • nuclear proteins (i.e. transcription factors) go in
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

nuclear localization signals

A

essential for nuclear protein import and is sufficient to direct normally cytoplamic protein to the nucleus

  • short sequence of positive amino acids
  • recognized by importin, delivers and escorts through nuclear pore
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

what is c-myc

A
  • transcription factor that binds to DNA and turns on transcription genes associated w cell replication
  • nuclear protein
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

cytoplasm

A

contains organelles

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

structure of mitochondria

A

encased by a double membrane

  • outermembrane = smooth and semi permeable - contains transport complexes
  • inner membrane - cristae - folds that form shelf like stuctures
  • matrix - inner compartment, contains DNA and ribosomes
  • mitochondria have its own DNA
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

cristae

A

folded shelves, contain ATP synthase

- more surface area = more ATP

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

mitochondria DNA

A

encodes ribosomal RNA, tRNA, ATP synthase, ETC proteins

-proteins imported from cytoplasm have mitochondrial localization sequence

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

mitochondria function

A 
-energy production (ATP) 
\+TCA cycle, ETC
-regulation of calcium ions 
-mediation of programmed cell death
-maintains pH gradient between intermembrane space and matrix
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

how mitochondria create ATP

A
  • TCA cycle: in matrix, take pyruvate, makes GTP, NADH, FADH2
  • ETC - takes electrons from NADH, passes them through proteins in inner membrane, adds e- to O2
  • hydrogen pumped out to crease gradient across inner membrane
  • hydrogen flow back in through ATP synthase to make ATP
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

how mitochondria grow

A

grow and divide by binary fission (like bacteria)

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

plastids

A
  • double membrane-bounded organelles
  • present in plants and some protists
  • main function: photosynthesis (chlotoplasts_ and storage (chromoplasts, leucoplasts)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

chloroplasts structure

A

-double membrane
-thylakoid membranes
-stroma - inside region, contains DNA and ribosomes
close to 100 genes are present that code for proteins involved in photosynthesis

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

thylakoid membranes

A
  • highly folded third membrane system of the chloroplast
  • stackks that contain proteins that bind to chlorophyll and other light absorbing pigments that are key in photosynthesis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

chloroplasts functions

A 
light reactions 
-make O2, ATP, NADH
-occur in thylakoids 
-photosystem I & II, ETC
Dark reactions (Calvin)
-use ATP and NADPH to concert CO2 to sugar 
-end product = glucose
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

origin of organelles

A

mitochondria and chloroplasts are believed to be originated from endosymbiosis - when large eukaryote engulfs prokaryote

  • mitochondria - proteobateria
  • chloroplasts - cyanobactera
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
49
Q

peroxisomes

A
  • tiny square shaped
  • crystalline arrays of enzymes
  • contain catalase for destroying toxic peroxides
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
50
Q

plant vacuoles

A
  • single membrane
  • storage of toxic waste materials (poison to predators)
  • storage of food, nutrients, ions, metabolites
  • hydraulic stiffness “turgor” of plant cell for support
  • can contain hydrolytic enzymes
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
51
Q

chromoplatst

A

organelles that synthesize and store pigments in flowers (specifically red, yellow, orange)
-attractant for pollinating insects

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

leucoplasts

A

storage organelles for synthesis of starch lipids or proteins

  • located in roots and non-photosynthetic tissues
  • amyloplasts - in potatoes, store starch
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
53
Q

insulin is a

A

peptide hormone secreted into the blood by beta cells in the pancreas
-islet of langerhans - part of the pancreas that contains a lot of beta cells

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

insulin structure

A

secrete protein, 51 amino acids

-signal peptire at the N-terminus, hydrophobic alpha helix recognized by ribosomes on rough ER

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

insulin function

A
  • secreted from beta cell upon rise in blood glucose

- binds to cell surface of muscle and fat cells: signals to import/store glucose

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

post translational proteolytic processing of insulin

A

-protease, signal protein in ER, cleaves off peptide at n terminus
makes pre-pro-insulin into pro-insulin

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

endomembrane system

A

dense network of closed membrane tubules, closed vesicles and closed sacs

  • divides cytoplasm into two parts: inside the sacs/tubes and the outside
  • completely different protein make up
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
58
Q

rough er (endoM system)

A
  • close to nucleus
  • ribosomes attached to outside
  • creates integral membrane proteins and secreted proteins
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
59
Q

smooth er (endoM system)

A
  • no ribosomes
  • contains metabolic enzymes
  • synthesis of lipids, functions in metabolism
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
60
Q

golgi complex (endoM system)

A
  • stacked series of flattened membrane sacs

- modifies proteins, carbs, ship them to sell surface

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

vesicles (endoM system)

A

lysosomes, peroxisomes, secretory vesicles that move to cell surface

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

functions of endomembrane system

A
  • sequestration of molecules/particles into cisternal space of vesicle
  • transportation of sequestered molecules/particles within the cytoplasm of the nucleus into/out of cell
  • chemical modification of sequestered molecules
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
63
Q

smooth ER function

A
  • lipid synthesis for membranes

- detoxification of hydrophobic toxins

64
Q

rough ER function

A
  • ribosomes make secreted proteins into cisternal space, integral membrane proteins in membrane
  • proteins are chemically modified
  • integral membrane proteins and secreted proteins have a signal sequence at the n-terminus that directs the ribosomes to the rough ER
  • pinches off and moves to golgi
65
Q

golgi function

A

-post office
-vesicles come from ER, fuse with cis
-move down to medial and trans
-pinches off trans, fuses with plasma membrane
vesicles are secreted

66
Q

how do we get integral membrane proteins into the plasma membrane?

A

proteins in vesicle are inserted in plasma membrane, lipid bilayers fure

67
Q

lysosome

A

-single membrane in endomembrane system
-cells recycling center
-digestive enxymes break down old cellular materials so we can reuse them
-

68
Q

phagocytosis

A

digestion of bacteria

-happens in lysosome

69
Q

secretion genes encode

A

membrane proteins that are involved in membrane traffic

70
Q

membrane traffic is

A

protein mediated and requires energy

71
Q

microfilaments

A

actin - smallest

  • spread throughout cytoplasm
  • two primary functions: cell shape and movement
72
Q

dynamic properties of actin

A
  • assemble and disassemble by noncovalent recersible addition/loss of actin monomers at the ends of filaments
  • polymerization requires energy by hydrolysis of ATP, releasing energy to the filaments that creates treadmilling
73
Q

actin filaments in cell shape

A

-stress fibers: bundles of actin filaments that help maintain skin cell shape and keeps cells elongated
-microvilli - filled with table actin bundles projecting from the cell surface
+allows for more absorption in the intestine by increasing surface area

74
Q

actin in structural support

A
  • focal adhesion: places where stress fibers attach to the plasma membrane and anchor cells to the substrate or adjacent cells
  • jointed to integrin receptors that bind extracellular matrix outside of cell
75
Q

actin in movement

A
  • drives membrane out to move the cell
  • contraction - back pact of the cell, actin-myosin interaction results in contraction
  • protrusion of pseudopod = treadmilling
76
Q

intermediate filaments

A
  • cable-like filament
  • very stable, used for structural purposes
  • nuclear lamins: supports nucleus, attachment points for DNA)
  • keratin filaments: hair, skin
  • neurofilaments: long neurons
77
Q

microtubule structure

A
  • tubes made out of alpha beta tubulin dimers

- have plus end and minus end (like actin)

78
Q

microtubule dynamics

A
  • dynamic instability: switches between growth and shortening at positive end
  • treadmilling - same as actin filaments
79
Q

microtubule organization

A

-organized in cells by microtubule organizing centers or centrosomes

80
Q

microtubule function

A
  • cell shapes and various kinds of movement (different from actin)
  • movement of chromosomes during cell division
81
Q

MTOC/centrosome

A
  • pair of centrioles surrounded by a pericentriolar matrix

- barrel shaped structures made of 9 sets of triplet microtubules

82
Q

microtubules in cilia and flagella

A
  • machines for cell mobility and moving particles
  • dynein motor proteins do work, using energy from ATP
  • microtubule walking
83
Q

microtubule-driven vesicle movement

A

movements of vesicles along microtubule using dynein(-)/kinesin(+)

84
Q

cell membrane function

A

all cells have plasma membrane

  • contain/hold contents of cell
  • phospholipid bilayer
85
Q

what do cell membranes contain?

A

lipids, proteins, glycoproteins that serve as receptors, channels, pores, transporters and anchors

86
Q

lipid rafts

A
  • less fluid, more rigid structure high in cholesterol

- concentration certain transmembrane proteins

87
Q

passive diffusion across cell membranes

A
  • flow is down concentration gradient until equilibrium reached
  • no energy needed
  • lipid soluble uncharged molecules (uncharged lipids, small hydrophobicmolecules)
88
Q

ion channel proteins across cell membranes

A
  • pores only let in specific ions through, gated by ligand bonding or voltage
  • essential in function of neurons
  • carried mediated diffusion - glucose carrier protein
  • no energy needed
89
Q

active transport across cell membranes

A
  • carriers can move molecules against their concentration gradient
  • need ATP and ion gradient
90
Q

what are the three types of active transports?

A
  • uniporter - transports one substance in one direction
  • symporter- transports two substances in one direction
  • antiporter - transports two substances in opposite direction
91
Q

endocytosis

A

moving complex molecules/particles into the cell

92
Q

what are the three types of endocytosis?

A

phagocytosis, pinosytosis, receptor-mediated endocytosis

93
Q

phagocytosis

A

large particles and small cells are engulfed inside vesicles and degraded

94
Q

pinocytosis

A

“cell drinking”

cells take up water into vesicles

95
Q

receptor mediated endocytosis

A

takes certain kinds of macromolecules into the cell

  • specific substance binds to cell membrane, clartherin coats the outside of membrane, vesicle pinches off, clathrin coat on vesicle surface brought into cell cytoplasm
  • fuses with a lysosome, releases contents
96
Q

exocytosis

A

fusion of a membrane vesicle to plasma membrane

97
Q

extracellular matrix (ECM)

A

connective tissue in animals

  • components are synthesized inside the cell then secreted out
  • glue that hold tissues together, bone, antlers, teeth
  • can tell a cell what to be
  • can keep cell alive: cells that lose attachments to matrix undergo apoptosis
98
Q

apoptosis

A

programmed cell death

  • important in neuronal death, creates fingers
  • no binding to EMC, external and internal signals can result in triggering a pathway that kills a cell
  • caspases= protease that breaks up DNA, kills the cell
99
Q

ECM acts as a

A
  • filter in kidney
  • basal lamina between blood vessels and kidney cells
  • small molecules can go through ECM
  • contains collagen and proteoglycans
  • within glomeruli, specialized ECM called basal lamina resides at the interface between blood and urine
100
Q

cartilage is made of

A

proteoglycans - proteins made w a lot of sugars

-negatively charges, repel each other and provide cushion

101
Q

integrins

A
  • integral membrane protein receptors of the ECM
  • bind extracellular matrix outside and actin inside cell
  • important in holding tissues together
102
Q

integrin function

A
  • link EMC to actin cytoskelton
  • cell adhesion
  • cell survival
  • cell migration
  • cell differentiation
103
Q

plant cell walls

A

strong and thick, complex

  • made of cellulose
  • protects against mechanical stress
  • allow organism to build and hold shape
  • glues cells together
  • limits the entry of large molecules and toxic materials and acts as barriers to infection
  • stable osmotic environment
104
Q

cell junctions

A

cell-cell adhesion - holds tissues together - interaction of proteins in cell membranes
-cell-cell communication - transport of molecules between cells

105
Q

tight junctions (occluding junctions)

A
  • holds cells tight together
  • skin epidermis, blood vessels, endothelial
  • forms quilter seal, stops movement of dissolved materials through cell space between epithelial cells
  • forms blood brain barrier
  • does not allow movement of membrane proteins inside membrane bilayers
106
Q

desmosomes

A

anchoring junctions

  • anchor intermediate filaments in the cell
  • holds cells together, but allow wide space betweek cell
  • coupled to keratin - skin epidermis
107
Q

gap junctions

A

communicating junctions

  • allow small molecules pass through
  • links cells together functionally
  • permits passage of molecules between two cells
  • made of connexins - connecting protein channels
108
Q

mitosis in prokaryotes

A
  • DNA is usually single chromosome in shape of circle
  • division cycle: cell elongation to DNA replication to DNA segregation to fission
  • in favorable environment, multiply every 30 min
109
Q

mitosis in eukaryotes

A
  • more complicated, everything must be distributed equally into daughter cells
  • cell division is rarely contiguous
  • cell cycle regulated
110
Q

cell cycle

A
  1. M phase - mitosis: cells separate chromosomes and divides into two daughter cells
  2. G1 phase - phase between M and S
  3. S phase - DNA synthesis
  4. G2 - gap between S and M
111
Q

interphase

A

G1, S, and G2 phase

112
Q

G0

A

in G1, cell arrested and does not divide

113
Q

cell cycle is controlled by

A

cyclin-dependent kinases (CDK)

  • CDKs are activated by association with a partner protein cyclin
  • each CDK-cyclin pair acts as a different phase to cell cycle to control progression through cell cycle
  • CDK are always present during cell cycle
114
Q

when a cell wanted to divide

A

cyclin is released so it can bind to CDK

  • cyclin changes CDK, exposes active site
  • protein substrate and ATP bind to CDK, protein substrate is phosphorylated
  • each CDK has specific protein targed
115
Q

when the cyclin and CDK are bonded, there are checkpointes

A

G1- DNA damage
S- incomplete replication/DNA damage
G2-DNA damage
M - chromosome unattached to spindle

116
Q

DNA condensation

A

DNA (negatively charged phosphates) is complexed with proteins called histones (positively charged) helps it tigtly form

117
Q

chromatin

A

DNA-histone complex creates nucleosome
-connected by linker DNA
further folding in mitosis

118
Q

polytene chromosome

A

made when DNA goes through endoreplication - replicated many times

119
Q

when are chromosomes in their most condensed state?

A

mitosis

120
Q

each chromosome at mitosis

A

consists of two identical copies of its DNA and two identical copied of each gene present in that chromosome

121
Q

chromatid

A

single copy of DNA

122
Q

centromere

A

what holds copies of chromatid together

-cohesin, a protein, helps hold them together

123
Q

chromosomes of each daughter cell after mitosis are

A

identical to the parent’s cell

124
Q

prophase

A
  • cytoskeleton breaks down, endomembrane system disperses
  • chromatin condenses to the mitotic chromosome form
  • the centrosome move to opposite sides of the nucleus, pushed by microtubules
125
Q

prometaphase

A
  • nuclear envelope breaks down
  • kinetichore forms are the centromere of each chromatid
  • microtubules attach to the chromosomes to build the spindles
126
Q

metaphase

A
  • chromosomes are alighted at the center of spindle, metaphase plate
  • microtubules are highly dynamic and chromosomes are shuffling around
  • building of mitotic spindle is complete
  • metaphase checkpoint
  • can prevent dividing, apoptosis
127
Q

anaphase

A
  • cohesin molecules are destroyed by cyclin-CDK

- one of the chromatids of each duplicated chromosome moved randomly to one pole, other chromatid moves to the opposite

128
Q

telophase

A
  • the cleavage furrow (animal cells) or cell plate (plant cells) forms the middle
  • spindle microtubules disassemble
  • nuclear envelope reforms around the cluster of chromosomes at each pole
  • the chromosomes decondense to the interphase form
129
Q

what are the three types of mitotic spindles?

A

-kinetochore: extend from the poles of the kinetochore
-polar microtubules: extent from one pole to the opposite pole
-astral microtubules: extend from the poles away from the spindle in an aster-like formation
+backwards from the pole

130
Q

how spindle forms

A
  • during prophase and prometaphase, microtubules cast out from centrosome pole, plus end leading by dynamic instability
  • attach to the kinetochore
131
Q

how chromosomes move apart

A

during anaphase, chromatids move toward poles

  • microtubules disassemble at centrome pole and at kinetochores
  • also moved with motors kinesin (+) and dynein (-) at the poles of the microtubules
132
Q

cytokinesis

A
  • starts at the beginning of telophase
  • ribbon of contractile actin filament is built between the daughter cells, forming contractile ring
  • ribbon separates, pulling the membrane and creating a cleavage furrow
  • works by combo of actin shortening and myosin motor activity
133
Q

meiosis I

A
  • homologous chromosome come together to pair along their entire length
  • doesnt happen in mitosis
  • homologous chromosome pairs separarte
134
Q

prophase I

A
  • synapsis: two homologs of each pair become attached to each other, forming tetrads
  • crossing over (genetic recombination) occurs between the chromatids of the two homologs at the chiasmata
135
Q

metaphase I

A

tetrads line up at the metaphase plate with the kinetochore of one homolog directed toward one pole and the kinetochore of the other homolog facing the oppoosite

136
Q

anaphase I

A

one entire homolog with its two chromatids does to one daughter cell, the other homolog goes to the other

137
Q

meiosis II

A

follows immediately after meiosis I without DNA synthesis
-like normal mitotic division, the two chromatids of each remaining chromosome separate from each other and go to opposite poles

138
Q

genetic diversity happens in two ways

A
  • random distribution of the two homologs during meiosis I and random assortment during meiosis II
  • crossing over between homologs during prophase of meiosis I
139
Q

anatomy of a sperm cell

A

-head contains DNA and a secretory vesicle called acrosome
+ contains enzymes to break down surface of the egg, nucleus
-midpiece - Neck: contains mitochondria that supply ATP to power the dynein required for microtubule sliding and movement
-flagellum- tail: contains 9+2 arrangement of microtubules and the motor molecule dynein

140
Q

zygote

A
  • fertilized egg
  • re-establishes diploid state
  • totipotent - can make all cell types
141
Q

what do sperm contribute to the zygote?

A

DNA and centriole

-centriole becomes centrosome which organizes spindle for mitosis)

142
Q

what do eggs contribute to the zygote?

A

DNA, organelles, nutrients, transcription factors, mRNAs

143
Q

what happens day 2-3 after the sperm meets the egg?

A

cells proliferate, form blastula

144
Q

what happens day 4 after the sperm meets the egg?

A

forms blastocyst, ~32 cells

145
Q

what happens day 5 after sperm meets egg?

A

inner cell mass appears, ~128 cells. first differentiation

146
Q

what happens day 6-9 after sperm meets egg?

A

implantation

147
Q

inner cell mass

A

grow and differentiation into ectoderm, mesoderm, and endoderm and germ cells

148
Q

gastrulation

A
  • massive movement of cells transform the blastula into an embryo with multiple tissue layers and distinct body axes
  • produces basic body plan
  • the cells of the embryo differentiate to produce germ layers, determined at blastula stage
  • germ layer gives rise to various organ systems
149
Q

what are the three different germ layers?

A

-ectoderm - outermost layer. develops into skin, hair, nails
-mesoderm - middle layer. develops into skeletal system, bones, heart, kidneys, blood vessels
endoderm - innermost layer. develops into the respiratory tract, liver, pancreas, gut

150
Q

what determines cell fate in early gastrulation?

A

environment

151
Q

what determines cell fate in late gastrulation?

A

it was already determined, will continue developing no matter where you put it

152
Q

how does environment determine cell fate?

A

cell-cell interactions: mediated by membrane proteins. other proteins change gene expression

  • cell-extracellular matrix interactions - target cell binds to ECM via receptor, resulting in changes in gene expression
  • secreted inducers: often growth factors, binds to receptors on surface and changes gene expression
153
Q

how do inducers regulate gene expression?

A

-inducer binds to receptor, signal sent from receptor to nucleus, gene expression is turned on or off

154
Q

c-myc is ____ for epidermis

A

necessary AND sufficient

155
Q

how does insulin get secreted from beta cells?

A

through the endomembrane system

156
Q

where would you find a ligase in a cell?

A

lysosome

157
Q

what would happen if you added a drug that causes depolarization of microtubules in a paramecium?

A

it would not be able to swim or move food particles

MCDB 1A (2 decks)

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