Chapt 4 Flashcards

1
Q

There is a relationship between the size and _________ of a cell and it’s _____________

A

Shape; function

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2
Q

What is the plasma membrane of a cell & its function

A

Cell membrane that forms a barrier separating the internal cal fluid & external fluid environment

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3
Q

What is a nucleus & its function

A

Largest organelle enclosed in a nuclear envelope. Contains DNA, nucleoplasm (fluid), & nucleolus

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4
Q

What is cytoplasm & its function

A

Cellular contents located between the membrane & nucleus, includes cytosol, organelles, & inclusions

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5
Q

What is cytosol

A

Intracellular fluid

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6
Q

What are organelles & what are the two types

A

Little organs that have a unique function & shape
- membrane bound: enclosed by a membrane
- non-membrane bound: not enclosed by a membrane

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7
Q

What are inclusions in the cell

A

Aggregates of molecules (melanin & nutrients)

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8
Q

What are the general cell functions

A
  • Maintain integrity & shape of cell
  • obtain nutrients & form chemical building blocks
  • dispose of wastes
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9
Q

What are phospholipids in the cell

A

Lipids of the plasma membrane

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10
Q

What is the phospholipid bilayer

A

Framework of the cell’s plasma membrane

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11
Q

What role does cholesterol play in the cell

A

Strengthens the membrane & stabilizes the membrane

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12
Q

What are glycolipids & where are they located in the cell

A

Lipids attached to carbs; located on the outer surface

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13
Q

What is glycocalyx

A

Formed by the glycolipid & glycoprotein; each person has their own pattern except identical twins

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14
Q

What are the functions of the plasma membrane

A

Physical barrier, selective permeability (regulates entry & exiting of ions, nutrients, & waste), electrochemical gradients/establishes & maintains an electrical charge difference between the ICF & ECF, & communication (contains receptors that recognize & respond to a molecular signal)

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15
Q

What are the types of membrane proteins

A
  • Integral proteins
  • peripheral proteins
  • transport proteins
  • cell surface receptors
  • identity markers
  • enzymes
  • anchoring sites
  • cell adhesion proteins
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16
Q

What are integral proteins

A

Embedded within & extend across the plasma membrane

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17
Q

Glycoproteins are what type of protein & what do they consist of

A

Integral protein; proteins w/ carbs

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18
Q

What are peripheral proteins

A

Not embedded within but are attached loosely to the external or internal surfaces of the membrane

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19
Q

What are transport proteins & what are the types

A

Regulate the movement of substances across the membrane; channels, carriers, pumps, symporters, & antiporters

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20
Q

What are cell surface receptors

A

Bind molecules called ligands

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21
Q

What are ligands & what membrane protein binds them

A

Molecules that bind to macromolecules; cell surface receptors

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22
Q

What are identity markers

A

Communicate to other cells that they belong to the body

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23
Q

What are enzymes as a membrane protein

A

Attached to either the internal or external surface; catalyzes reactions

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24
Q

What are anchoring sites

A

Secure the cytoskeleton to the plasma membrane

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25
Q

What are cell adhesion proteins

A

Regulate cell-to-cell attachments

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26
Q

What is membrane transport within The cell & its types (just name)

A

Process that describes the entry or elimination of substances across the plasma membrane
Passive & active process

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27
Q

What is the passive process in membrane transport

A

Does not require cellular energy but moves a substances kinetic energy to move it down its concentration gradient

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28
Q

What is the active processes of membrane transport

A

Requires cellular energy because moves a substance up its concentration gradients

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29
Q

What are examples of passive membrane transport

A

Diffusion and osmosis

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30
Q

What are conditions that affect the rate of a substances diffusion

A

1.) the steepness of a concentrationgradient (difference in the concentration of a substance between 2 areas); steeper the gradient, the faster diffusion
2.) temp: the higher the temp, the higher the kinetic energy of a substance, the greater the rate of diffusion

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31
Q

What is diffusion & what type of membrane transport is it

A

net movement of a substance from high to low concentration, continues until substances reach equilibrium (molecules equally distributed), passive

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32
Q

What are the types of cellular diffusion

A

Simple, facilitated, channel-mediated, carrier mediated

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33
Q

What is simple diffusion

A

Solutes that are small & nonpolar & move down their concentration gradient; no transport protein is required & can cross the plasma membrane on its own

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34
Q

What is facilitated diffusion

A

Solutes that are small but charged & polar & cannot pass through the hydrophobic region of the membrane; require assistance to be transported in & out of the cell

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35
Q

What is channel-mediated diffusion

A

Movement of small ions across the plasma membrane thru water-filled protein channels

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36
Q

What are the 2 types of channels in a channel-mediated diffusion

A

Leak channel: specific to one ion & is continuously open
Gated channel: usually closed but opens in response to a stimulus (chemicals, light, voltage) & then stays open for a few seconds before reclosing

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37
Q

What is carrier-mediated diffusion

A

Movement of small polar molecules (sugars or amino acids) by a carrier protein

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38
Q

What is a carrier protein & A uniporter

A
  • Transports substances (like glucose) after binding to it; then changes shape before the substances are moved to the other side
  • a carrier protein that transports only one substance
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39
Q

What is osmosis

A

Passive movement of water thru the plasma membrane due to the different concentrations of water on either side of the membrane

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40
Q

What are aquaporins & where are they located

A

Integral protein water channels

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41
Q

What is a permeable solute & some examples

A

Pass thru bilayer ( O2, CO2, and Urea)

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42
Q

What ave non-permeable solutes & examples

A

Prevented from crossing the bilayer (charged, polar, or large solutes like ions, glucose, & proteins)

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43
Q

What is concentration gradient across the plasma membrane

A

Differences in solute concentration exist been ICF & ECF because of the regulated transport of solutes

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44
Q

Water moves ___________ its concentration gradient until it reaches ____________________

A

Down; equilibrium

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45
Q

Water moves in the direction of _____________ solute concentration

A

Higher (or less water concentration)

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46
Q

What is osmotic pressure

A

Pressure exerted by the movement of water across a semipermeable membrane due to the difference in solute concentration

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47
Q

What is hydrostatic pressure

A

Pressure exerted in a fluid on the inside wall of its container

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48
Q

Water movement across the cell can affect the cells ___________

A

Shape

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49
Q

What is tonicity

A

The change in shape thru volume & pressure changes by the movement of water

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50
Q

What is isotonic

A

Equal solute concentration between the ICF and ECF, & therefore the movement of water into & out of cell is constant; no change in cell shape

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51
Q

What is hypotonic

A

Lower concentration of solutes in the ECF than in ICF, so water
Enters the cell & exits ECF; cells volume increases & cell swells

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52
Q

What is lysis & what tonicity can it happen with

A

Cell rupture; hypotonic

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53
Q

What is hemolysis & what tonicity can it happen

A

Rupture of erythrocytes (RBC’s) & hypotonic

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54
Q

What is a hypertonic solution

A

Higher concentration of solutes in the ECF than ICF, so water exits the cell & enters the ECF; cells volume decreases & cell shrinks

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55
Q

What is crenation & what tonicity relates

A

Cell shrinking; hypertonic

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56
Q

What is active transport & its types

A

Movement of a solute against its concentration gradient (low to high concentration); primary active transport & ion pumps

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57
Q

What is primary active transport

A

Energy is captured from the breakdown of ATP to more substances across the membrane (usually called pumps)

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58
Q

What are ion pumps

A

They pump ions across the membrane up their gradient

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59
Q

What are sodium potassium pumps

A

An exchange enzyme pump that hydrolyzes ATP

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60
Q

What is the process of a sodium potassium pump

A

1.) 3 sodium ions & ATP bind sites on the pump in the ICF
2.) ATP is split into ADP & Pi, the pump changes shape & release Na+ into the ECF, while the free Pi remains attached
3.) 2 potassium ions from the ECF bind to the pump, the Pi is released
4.) the pump undergoes another shape change, releasing K+ into the ICF

61
Q

What is secondary active transport

A

Moves substances up its concentration gradient by using energy provided by another substance being transported via kinetic energy

62
Q

What is symport

A

Movement of the 2 substances in the same direction (ex. Glucose/Na+ symporter)

63
Q

What is an antiport

A

Movement of the 2 substances opposite directions (ex.Na+/H+ antiporter)

64
Q

What is vesicular transport (aka bulk transport) & what are the types

A

Requires energy to move large material via vesicular transport; exocytosis, endocytosis, phagocytosis, pinocytosis

65
Q

What is a vesicle

A

Membrane bound sac filled with materials

66
Q

What is exocytosis

A

Secretion of large substances or large amounts from the ICF to ECF

67
Q

What are the steps of exocytosis

A

1.) a vesicle within the ICF nears the plasma membrane
2.) the vesicle fuses with the plasma membrane
3.) the plasma membrane opens toward the ECF
4.) release of substances in the vesicle occurs & the vesicle membrane integrates into the plasma membrane

68
Q

What is endocytosis

A

Uptake of large substances or large amounts of substance from the extracellular fluid into the intracellular fluid

69
Q

What is invagination

A

Small area of plasma membrane folds inward into the cytosol

70
Q

What is phagocytosis

A

Cellular eating

71
Q

What are the steps of phagocytosis

A

1.) cell forms extensions called pseudopodia to surround the particle
2.) once surrounded it gets enclosed within a membrane sac called a vesicle
3.) vesicle is moved into the ICF where it fuses with a lysosome so that the material can be degraded

72
Q

What is pinocytosis

A

Cellular drinking; occurs when cells internalize droplets of ECF

73
Q

What is receptor-mediated endocytosis & what does it allow the cell to do

A

Uses receptors on the membrane to bind molecules within the ECF & bring them into the cell; allows the cell to obtain bulk quantities of certain substances

74
Q

What are examples of receptor - mediated endocytosis

A
  • Transport of cholesterol from blood to cell
  • cholesterol is bound to a lipid transporter called low-density lipoprotein (LDL)
  • LDL’s move can be moved into the cell via receptor-mediated endocytosis when they bind to the cell’s LDL receptor
75
Q

What is membrane potential

A

The form of potential energy stored in the electrical charge difference between the ECF & ICF

76
Q

What is resting membrane potential (RMP)

A

Membrane potential of a cell at rest

77
Q

What are the requirements of establishing & maintaining RMP

A
  • Must be an unequal distribution of ions & molecules across the cell’s membrane
  • the amount of positive & negative charges are not equally distributed at the membrane
78
Q

What does the nucleus do & produce

A

Houses DNA molecules that serve as the genetic instructions for the synthesis of proteins; produces ribosomal subunits in the nucleolus, which are exported into the cytoplasm for assembly into ribosomes

79
Q

What is the nuclear envelope

A

Double membrane that encloses the nucleus

80
Q

What is the nucleoplasm

A

Fluid located within the nucleus

81
Q

What are nuclear pores

A

Open passageways formed by proteins that extend thru the nuclear envelope

82
Q

What is the nucleolus

A

Produces the large & small ribosome subunits

83
Q

What are the 4 deoxyribonucleotides

A

A-adenine
G-guanine
C-cytosine
T-thymine

84
Q

What are histones

A

Nuclear proteins that wind DNA

85
Q

What is a nucleosome

A

Complex created by histones

86
Q

What is chromatin

A

Mass of DNA found in non-dividing cells

87
Q

What is a chromosome

A

Tightly coiled masses of chromatin in dividing cells

88
Q

What are genes

A

Segments of nucleotides within DNA that provide instructions for protein synthesis

89
Q

What is transcription & where does it occur

A

Formation of an RNA copy from a DNA gene; nucleus

90
Q

What is translation & where does it occur

A

Synthesis of proteins by ribosomes from the RNA copy; cytosol

91
Q

What are the ribonucleotides

A

A-adenine
G-guanine
C-cytosine
U-uracil

92
Q

What does RNA polymerase do in the process of transcription

A

Assembles the ribonucleotides by complementary base pairing RNA nucleotides with DNA

93
Q

How are the nucleotides between DNA & RNA held together

A

Hydrogen bonds

94
Q

What is the first major event in transcription & what happens

A

Initiation; DNA double helix is unwound by DNA Helicase
RNA polymerase synthesizes RNA by binding to the promoter sequence (start point) of the gene
* RNA polymerase reads only 1 strand of DNA double helix

95
Q

What is messenger RNA (mRNA)

A

Copy of DNA that exits the nucleus

96
Q

What is a template strand

A

Strand of DNA that is copied into RNA (mRNA)

97
Q

What is the coding strand

A

Uncopied version of DNA

98
Q

What is the 2nd major event of transcription & what happens

A

Elongation; as RNA polymerase moves down DNA template strand, free ribonucleotides of RNA (A, U, G, C) are base-paired with the deoxyribonucleotides of the template strand
* mRNA is lengthened in the process

99
Q

What is the 3rd major event in transcription & what happens

A

Termination; when RNA polymerase reaches the terminal region of the gene, it releases the DNA & mRNA
* DNA rewinds into double helix and the mRNA is a copy of the gene that will be used to translate protein

100
Q

What is translation & where does it occur

A

Synthesis of a new protein that takes place at the ribosomes

101
Q

What is a required structure for translation

A

Ribosomal RNA (rRNA): two subunit organelle

102
Q

What 3 spaces does alarge subunit consist of & what occurs at each one

A

A - aminoacyl site: where new amino acids are added
P-peptidyl site: where the newly forming polypeptide is held
E-exit site: where the empty tRNA is held

103
Q

What happens in the initial stage oftranslation

A
  • The small ribosomal subunit, the mRNA strand, & the charged tRNA come together first at the start codon
  • the large ribosomal subunit binds to the small subunit positioning the tRNA in the P site
104
Q

What is a codon

A

Each 3 base unit of ribonucleotides

105
Q

What is a start codon

A

Signal for the beginning of translation (AUG)

106
Q

What is a stop codon

A

The point where mRNA translation ends

107
Q

mRNA is what is transcribed from DNA & read (translated) into protein. mRNA is read ______ bases at time

A

3

108
Q

What happens in the elongation part of translation

A
  • A charged tRNA with a complimentary anticodon base pairs with the codon of the mRNA in the A site
  • a peptide bond forms between amino acids, releasing the “Met” from its tRNA
  • the ribosome more 3 nucleotides (1 codon) down the mRNA strand
  • the uncharged tRNA is released & process repeats
109
Q

What occurs in the termination step of translation

A
  • Occurs when a stop codon is reached
  • the ribosomes disassemble, & the newly synthesized protein & mRNA are released,
110
Q

What is a polyribosome

A

An mRNA with many ribosomes along its length

111
Q

What are the functions of the rough ER & what type of organelle

A

Synthesis: synthesizes proteins for secretion, incorporation into plasma membrane, & as enzymes within lysosomes
Processing molecules: modify & store proteins
Organelle formation: helps for peroxisomes
Vesicle formation: forms transport vesicles for shipping of proteins to Golgi apparatus
* membrane-bound organelle

112
Q

What are the functions of smooth ER & what type of organelle is it

A

Synthesis: site of lipid synthesis
Processing molecules: carbohydrate metabolism
Organelle formation: detoxifies drugs & poisons
Vesicle formation: forms transport vesicles for shipping to Golgi apparatus
* membrane bound

113
Q

What are the functions of the Golgi apparatus

A

Synthesis: forms proteoglycans
Processing molecules: modify & store protein
Organelle formation: synthesizes digestive enzymes for lysosomes
Vesicle formation: forms secretary vesicles for delivering components of the plasma membrane & releasing contents from the cell by exocytosis

114
Q

What is the process of proteins from ribosomes in the RER

A
  • Ribosomes in RER synthesize protein & package it into transport vesicle
  • vesicle leaves RER & fuses with Golgi apparatus
  • proteins are modified as they move thru the Golgi apparatus
  • modified proteins are packaged into secretory vesicles & released from the Golgi
  • secretary vesicles either
    - merge w/ plasma membrane & insert contents into the membrane or release proteins via exocytosis
    - merge with lysosomes
115
Q

What do lysosomes do

A

Digestion: break down molecules by fusing with resides, remove damaged organelles & cellular components, & break down cellular components(autolysis)

116
Q

What do peroxisomes do

A

Digestion: break down fatty acids, amino acids, & urea w/ hydrogen peroxide
Synthesis: helps form certain lipids (ex. Bile salts)

117
Q

What is included in the endomembrane system

A

Plasma membrane, nuclear envelope, & various membrane- bound structures that include the ER - Golgi apparatus, lysosomes & peroxisomes

118
Q

What is the function of mitochondria

A

Energy harvesting: digest organic molecules to produce ATP by aerobic cellular respiration (aka powerhouse)

119
Q

What do ribosomes consist of & the 2 types

A

Consist of a large & small subunit
- bound ribosomes: attached to external surface of RER membrane
- free ribosomes: suspended within the cell

120
Q

What do bound ribosomes synthesize

A

Proteins destined to be fused with the plasma membrane, exocytosis from the cell, housed within lysosomes

121
Q

What do free ribosomes synthesize

A

Proteins for use within the cell

122
Q

What forms the cytoskeleton & what are its functions

A

3 different proteins (microfilaments, intermediate filaments,microtabules)
- Structural support: maintains cell shape, protein support of microvilli, cilia, & flagella; stabilizes cell junctions; organizes organelles
- cell division: separates chromosomes during cell division & splits cells into 2 daughter cells
- movement: facilitates cytoplasmic streaming; involved in the movement of vesicles within a cell; participates in muscle contraction

123
Q

What are The functions of the centrosome

A

Synthesis: organizes microtubules & supports their growth in non-dividing cells
Cell division: directs the formation of the mitotic spindle in dividing cells

124
Q

What are the functions of proteasomes

A

Protein digestion: degrades proteins that are damaged, incorrectly folded, or are no longer needed
Quality assurance: controls the quality of exported cell proteins

125
Q

What is cilia

A

Hair-like projections that move mucus toward the throat so it can be expelled from the respiratory tract

126
Q

What is flagella

A

Whip-like structure that helps propel sperm

127
Q

What is microvilli

A

Thin microscopic extensions that increase the plasma membranes surface area to increase membrane support

128
Q

What are membrane junctions

A

Connect & support cells

129
Q

Where is a tight junction located & what is it

A

Located at apical surfaces of adjacent cells & function to seal off the intracellular space & prevent substances from passing between cells

130
Q

What are desmosomes, where are they located, & what do they do

A

Consist of protein plaques & filaments, located on the internal surface of the plasma membrane of adjoining cells, provide structural integrity to the cells exposed to stress

131
Q

What are gap junctions & connexons

A

Provides a direct passageway for substances to travel between neighboring cells
- transmembrane protein

132
Q

What is mitosis

A

Somatic cell division of nucleus

133
Q

What is meiosis

A

Sex cell division of the nucleus

134
Q

What is a somatic cell

A

All cells but sex cells

135
Q

What are daughter cells

A

2 identical cells that arise after a cell undergoes cell division

136
Q

What is the broad definition of interphase

A

Cellular preparation for division (3 steps)

137
Q

What happens in the G1 stage of interphase

A

Cells grow and produce double their organelles

138
Q

What happens in the S phase of interphase & what are the required materials

A

DNA strands are duplicated; DNA polymerase & a large # of deoxyribonucleotides

139
Q

What happens in the G2 phase of interphase

A

Centrioles are completely replicated, & enzymes needed for cell division are created

140
Q

What are sister chromosomes

A

Replicated DNA strands

141
Q

What is a centomere

A

A region that keeps the sister chromatids joined together

142
Q

When do chromosomes form in the major phase

A

At the separation of sister chromatids

143
Q

What happens in the prophase stage

A

Chromosomes appear as chromatin coil
Nucleolus & nuclear envelope disappear
Spindle fibers from centrioles form ascentrioles move to opposite ends of the cell

144
Q

What happens during metaphase stage

A

Centromeres on chromosomes attach to spindle fibers(centriole) & they align along the equatorial plate

145
Q

What is the anaphase stage

A

Sister chromatids move toward opposite ends of the cell (sister chromatids are now called chromosomes), & cytokinesis begins creating a cleavage furrow (pinching in the cell)

146
Q

What happens in telophase stage

A

Chromosomes uncoil to form chromatin
A nucleolus re-forms within each nucleus
Spindle fibers break up & disappear
Nuclear envelope forms around each set of chromosomes
Cytokinesis continues as cleavage furrow deepens

147
Q

What is cytokinesis

A

Division of cytoplasm between two newly formed cells

148
Q

What is a cleavage furrow

A

Intention created by the contraction of microfilament proteins( located in the plasma membrane) at the cells equator