Cell Division Flashcards
1
Q
Genome
A
all the DNA within the cell
2
Q
Zygote
A
common ancestor of all human cells
3
Q
Human somatic (body) cells contain how many chromosomes?
A
46 chromosomes
-23 copies of paired chromosomes
sex cells only have half the number of chromosomes a body cell would have
4
Q
Homologous chromosome pairs
A
are the 2 different copies of the same chromosome in a diploid organism
- one is given by the mother
- one is given by the father
Same size (except X and Y) carries same genes (except X and Y) Genes in same loci (except X and Y) can have different alleles not held together by a centromere
5
Q
Sister Chromatids
A
Only exist after DNA replication (100% identical)=Dyads
- same size
- carries same genes
- genes in same loci
- same alleles
- held together by a centromere
Referred as Replicated homologous chromosomes:
-46 replicated homologous chromosomes=23 pairs of homologous chromosomes
6
Q
Dyads
A
replicated chromosomes that look like an X
7
Q
Centromeres
A
Link sister chromatids together to form a dyad
-also assemble kinetochores
8
Q
Kinetochores
A
are proteins that orient themself on either side of a dyad centromere
-attach microtubules to help separate sister chromatids during karyokinesis
9
Q
Karyokinesis
A
process where one parent nucleus divides to form two daughter nuclei
10
Q
Cytokinesis
A
physical process of cell division
- process that occurs after karyokinesis
- physically separates the cytoplasm and cell membrane
11
Q
Ploidy
A
number of chromosome sets four in a cell
12
Q
Diploid cells
A
cells that contain two complete sets of chromosomes
Human somatic cells have a diploid number of 46 chromosomes which means each set contains 23 pairs
13
Q
Haploid cells
A
have half the number of chromosomal sets as a somatic cell
-uniquely describes gamete cells
Human genets have a haploid number of 23 chromosomes-they contain just one chromosomal set
14
Q
Gametes
A
Haploid cells
-contain 23 chromosomes
used by organisms during sexual reproduction
15
Q
Germ cells
A
divide by meiosis to form gametes
- diploid
- 46 chromosomes
16
Q
Cell Cycle
A
composed of two broad phases
1) Interphase
- 90% of cell cycle, where most cells are found
2) M Phase (Mitosis)
- karyokinesis occurs (division of the replicated DNA and nucleus)
- followed by cytokinesis
Go-Gap Phase 1 (G1) of interphase Sam- Synthesis Phase (S) of interphase Go-Gap Phase 2 (G2) of interphases Make-Mitosis of the M phase Cake- Cytokinesis of the M phase
17
Q
Gap Phase 1 (G1): of interphase
A
cell potential grows in preparation of a future division
- cell produces more cytoplasm, proteins, and organelles
- assess conditions if not favorable it will enter G0 phase.
- if conditions are favorable- proceeds to S Phase
18
Q
Gap Phase 0 (GO) of interphase
A
cells that will not divide after being made are found here -go about normal function EX: -neuron cells will send action potential -muscle cells will contract NO DIVIDING
19
Q
Synthesis Phase of Interphase
A
where a cell will replicate its genome in preparation of an ensuing cell division
-after replication cell enters G2 phase of interphase
20
Q
Gap Phase 2 (G2) of interphase
A
cell continues to grow and prepare for division
replicates organelles
checks for:
- accuracy of DNA replication
- Mitosis promoting factor (MPF)
21
Q
What are the four main phases of Mitosis?
What does a Diploid parent nucleus produce?
A
2 genetically dental diploid daughter nuclei
Prophase
Metaphase
Anaphase
Telophase
22
Q
Prophase of Mitosis (M Phase of the cell cycle)
A
- Chromatin condenses into chromosomes and become more visible
- nucleolus and nuclear envelope begin to disappear
- spindle apparatus beings to form
23
Q
Metaphase of Mitosis (M phase of the cell cycle)
A
Spindle apparatus guide chromosomes to the cell equator called the metaphase PLATE
-Dyads lined up in a single fie at the end of meta phase
24
Q
Anaphase of Mitosis (M phase of the cell cycle)
A
Shortest step of mitosis
Kinetochore microtubules shorten to pull centromere apart
-sister chromatids now called chromosomes are pulled toward opposite poles
-Polar spindle fibers bigin to elongate the cell
25
Telophase of Mitosis (M phase of the cell cycle)
Chromosomes arrive at opposite poles and begin to decondense
- nuclear envelope material surround east set of chromosomes
- mitotic spindle breaks down
- spindle fibers continue to push poles apart
26
Cytokinesis: animal cells
begin in late anaphase by formation of a cleavage furrow
| -creates a contractile ring that gets together until it eventually pinches the cell in two
27
Cytokinesis: Plant cells
begin around telophase
- Golgi apparatus releases vesicle and creating a cell plate
- Cell plate transforms into the middle lamella which cements adjacent plant cells together
28
What are some mutations that cause a cell to become more cancerous?
mutations in protooncogenes and tumor suppressor genes
29
Binary Fission
how archaea, bacteria, and mitochondria/chloroplasts (organelles) reproduce
- replicate their genome as cell division is taking place (replication of DNA and division of cell occur at the same time)
- No spindle apparatus
30
Meiosis
involves same general steps as mitosis
- Meiosis occurs twice (mitosis only occurs once)
- produce a total of 4 haploid daughter cells from one diploid parent
```
2 parts:
Meiosis I-homologous chromosomes are split
-reductional division
-ploidy of each cell will be halfed
Meiosis II-sister chromatids split
-looks a lot like mitosis;
```
31
Prophase I
chromatin condenses into chromosomes
- nucleolus disappears
- nuclear membrane disassembles
- paring of homologous chromosomes and crossing over occurs which creates genetic diversity
32
Genetic recombination
occurs when crossover event produces chromosomes that haven't been seen in either parent
-make genetically diverse offspring
33
Metaphase I
-bivalents/tetrads line up on metaphase plate duet meiotic spindle apparatus
34
Anaphase I
separates homologous chromosomes from each other by kinetochore microtubule shortening
- pulled toward opposite poles of the dividing cell
* * separates homologous chromosomes; sister chromatids not separated here
Will not start unless one chiasmata Is recognized
35
Telophase and Cytokinesis I
Telophase I
-meiotic spindle disappears as nuclear envelopes form
Cytokinesis I:
animals-formation of cleavage furrow
plant-formation of cell plate
36
Prophase II
chromatin condensing into chromosomes
- nucleoli disappearing
- nuclear envolope disintegrating
- meiotic spindle apparatus is formed
37
Metaphase II
just like metaphase in mitosis
Spindle apparatus guide chromosomes to the cell equator called the metaphase PLATE
- Dyads lined up in a single fie at the end of meta phase
* *each cell will have a haploid number of chromosomes
38
Anaphase II
pull sister chromatids of each chromosome apart at the centromere
- doubles the number of chromosomes in each cell
- pull chromosomes to opposite poles
39
Telophase II
reforms a nuclear envelope around each chromosome set
- create two new daughter nuclei
- chromosomes will decondense back into chromatin
- nucleoli will reappear in each nucleu
40
Cytokinesis II
sepearts each daughter nucleus into two new cells
- produces findal product
- four haploid daughter cells
41
Chromatin
general packaging of DNA around histone proteins
- helps condense DNA to fit within the nucleus of the celll
- exist in chromosomes during mitosis and meiosis
42
DNA organization
DNA wraps around proteins called HISTONES forming a complex called nucleosome.
each nucleosome contains 9 histones
43
Euchromatin
- represents parts of your DNA that consists of "loosely-packed" nucleosomes
- its easier for RNA polymerases to access the DNA code and transcribe our genes
44
Heterochromatin
represents parts of your DNA that consists of tightly packed nucleosomes
-these areas of DNA tend to be inactive in transcription
45
DNA helicase
seperates complementary strands at the replication fork
46
SSB
Single stranded binding proteins
| -proteins that prevent two strands from coming together after they seperate
47
Topoisomerase (DNA gyrase)
relaxes the DNA double helix from the tension that opening the helix created
48
Primase
Provides a 3'OH group for DNA polymerase to attache nucleotides to
49
DNA polymerases
class of enzymes that extends DNA in the 5' to 3' direction
50
DNA sliding clamp
Helps hold DNA polymerase to the template strand
51
DNA ligase
Glues together separate pieces of DNA
52
Telomerase
Adds repetitive DNA to the ends of eukaryotic chromosomes which prevents critical information from being lost
53
Operon
a group of of related genes are under the control of one promotor site
Function:
-makes sure the cell conserves its resources unless the resources are required
54
Lac Operon
HoOperon seen in E. Coli
- ex: inducible operon-usually inactive unless its induced to become active
- induced when glucose is not present but lactose is
Controls 3 genes:
LacZ
LacY
LacA
genes code for proteins that are used in metabolism of lactose
55
How is the Lac operon controlled
1. Lac repressor protein
- encoded by the gene LacL-not apart of lac operon
- constitutively expressed-gene is always being transcribed and translated
- repressor binds to the operator, RNA polymerase will not be able to bind effectively to the DNA and lac genes will be transcribed and translated at low levels
- IN the presence of lactose, allolactose will bind to the lac represser protein, causing a conformational change and cannot bind operator ration
2. cAMP levels and catabolite activator protein (CAP)
56
What are the three main types of mutations?
1. base substitutions (point mutations)
2. Insertion
3. Deletion
57
Point mutations
or called base substitutions
-occur when one nucleotide is replaced by a different nucleotide
3 types:
1. Silent
- change in the DNA code result in no change in what amino acid the codon codes for
2. Missense mutation:
- change in the DNA code results in the codon now coding for a different amino acid
- conservative missense mutation-mutated amino acid has the same properties as the unmated amino acid
3. Nonsense mutation
- codon is mutated to a stop codon
- protein shorter and can be detrimental to protein function
58
What happens when a histone protein is acetylated?
Acetylation of histones will remove their positive charge and loosen up the attraction between histones and negatively charged DNA generating euchromatin (Loose DNA)
WHICH INCREASES THE RATE of Transcription
59
Duplication mutation
piece of DNA is copied then reinserted into DNA
| -can cause a frameshift mutation
60
Translocation mutation
when one sequence of nucleotides is excised and reinserted into the DNA sequence somewhere else
-can cause a frameshift mutation
61
Inversion mutation
type of mutation where a sequence of DNA is excised and flipped and reinserted back into the DNA
62
Mismatch Repair
DNA polymerase can't catch all its mistakes
| -cell marks the uncaught errors so they can be replaced with the correct sequence
63
Nucleotide excision repair
repair mechanism for DNA that has been damage.
| -damaged strand is cut out and replaced with the correct sequence based on complementary base pairing
64
2 life cycles of viruses
Lysogenic cycle
- viral nucleic acid will insert itself into the host's genome
- beneficial to virus because its nucleic acid will be replicated whenever the hosts DNA is replicated
- virus is dormant and does not harm the host
Lytic cycle
- virus takes over the host's cells's machinery and does en up harming the host
- breaking apart host genome and replicating many copied of viral nucleic acid; make viral proteins which can lyse (break apart) the host cell and go infect other cells
65
HIV
human immunodeficiency virus
- RNA virus/retrovirus-a virus that stores its genetic material as RNA
- carry an enzyme called reverse transcriptase which allows them to convert their RNA into complement DNA (cDNA)
66
wild type allele
normal allele that is most common in nature
67
Hemizygous
individuals will only have one copy of an allele instead of two
68
penetrance
the proportion of individuals who exhibit the phenotype of an allele for a given gene
69
Complete penetrance
vs
Incomplete penetrance
the trait is expressed in the full population that has the allele
when the trait is only expressed in only part of the popuatonin that has the allele
70
Expressivity
degree of a certain phenotype
71
Incomplete dominance inheritance
an intermediate between two phenotypes
Ex: white with red flow producing pink flower
72
Codominance inheritance
contribution of both alleles will be seen
Ex: Blood typing:
A and B= AB blood
-no blood type is dominant
73
Epistasis
interaction between genes
| -one gene can affect the expression of a different gene
74
Pleiotropy
-one gene gives many different traits
CYSTIC FIBROSIS
75
Polygenic inheritance
multiple genes affect one trait with continous variation
| -one trait given by many different genes
76
Law of independent assortment
in meiosis, homologous chromosomes will line up on the metaphase plate independently of one another
-seperation of alleles is totally random
77
Nondisjunction
the failure of one or more chromosome pairs to separate properly during anaphase
-results in production of daughter cells with the incorrect number of chromosomes
78
Aneuplooidy
abnormal number of chromosomes in the resulting cells
| -caused by nondisjunction
79
Down syndrome
Trisomy at chromosome 21
- resulting from nondisjunction at chromosome 21
- not fatal
80
Turners Syndrome
X chromosome monosomy that affects females
| -physicial abnormalities and sterility
81
Klinefelters syndrome
Sex chromosome trisomy in males
XXY sex chromosomes
82
true breeding organism
homozygous for its traits AA or aa
83
F1 generation
produced after true breeding parents are crossed
| -first generation of offspring
84
Linked genes
found closure together on the same chromosome
| -
85
haplotype
a group of genes that are located so close to each other on a chromosome that they tend to be inherited together
86
Sucrose
Glucose + fructose disaccharide
87
Lactose
Galactoase + glucose disaccharide
88
Maltose
Glucose + glucose disaccharide
89
atom
the smallest unit o feather that still retains the chemical properties of the element
90
Cellulose
structure component in plant cell walls
- B bonded polysaccharide
- linear strands packed rigidly in paralel
91
Chitin
structural component of fungi cell walls and insect exoskeletons
-beta bonded polysaccharide with nitrogen added to each monomer
92
RNA world hypothesis
RNA dominated Earth's primordial soup before there was life
| -RNA developed SELF REPLICATING mechanism and later could catalyze reactions such as protein synthesis
93
Nucleoplasm
cytoplasm of the nucleus
94
nuclear envelope
is the membrane of the nucleus
- contains 2 phospholipid bilayer (one inner and one outer)
- perinuclear space
95
nuclear lamina
provide structural support to the nucleus
| -regulate cell division and DNA
96
Nucleolus
dense area responsible for making making rRNA
| -produce ribosomal subunits
97
Ribosomes
not organelles
| -small factories that carry out translation
98
Eukaryotic Ribosomal Subunits
60s and 40s subunits assemble in the nucleoplasm and form the complete ribosome in the cytosol (80s)
99
Prokaryotic Ribosomal Subunits
50s and 30s assemble in the nucleoid and form complete ribosome in the cytosol 70s
100
Golgi Apparatus
made up of cisternae (flattened sacs) that modify and package substances
101
Lysosomes
membrane bound organelles that breakdown substances via hydrolysis taken in through endocytosis
102
Endomembrane system
group of organelles and membranes that work together to modify, package, and transport proteins and lipids
composed of
Nucleus, smooth and rough ER, Golgi apparatus,, lysosomes, vacuoles, cell membrane
103
Mitochondria
power house of the celll
| -producing ATPfor energy through cellular respiration
104
Cytoskeleton
```
provide structure
function in the cytoplasm
```
3 types:
microfilament
intermediate filaments
microtubules
105
Microfilament
smallest type of cytoskeleton
- composed of double helix of actin filaments
- mainly involved in cell movement
106
Functions of microfilaments
1 Cyclosis
2. Cleavage furrow
3. Muscle contraction
107
Intermediate filaments
middle size type of cytoskeleton
| -structural support
108
Lamins
type of intermediate filament
| -helps make up the nuclear lamina
109
Nuclear lamina
network of fibrous intermediate filaments which support the nucleus
110
Microtubules
largest type of cytoskeleton
- give structural integrity to cells, cilia and flagella
- hollow tubes with walls made of tubular
111
Tight junctions
form water-tight seals between cells to ensure substance pass through cells and not between them
112
desmosomes
provide support against mechanical stress
| -connects neighboring cells via intermediate filaments
113
adherens junctions
similar in structure and function to desmosomes
| -connects neighboring cells via actin filament
114
Gap junctions
allow passage of ions and small molecules between cells
115
Isotonic solutions
have the same solute concentrations as the cells placed in them
116
hypertonic solution
have a higher solution concentrraiotn than the cells places in them
- causing water to leave the cell
- cell shrivels
117
Hypotonic solutions
have a lower solute concentrations than cells place them in, causing water to enter the cell
-cell swells up
118
Lysis
bursting of the cell when to much water enters via hypotonic solutions
119
Aerobic Cellular Respiration
-phosphorylate ADP into ATP by breaking down glucose and moving electrons around
```
Involves four catabolic processes:
glycolysis
pyruvate manipuations
Krebs cycle
oxidative phosphoryation
```
120
Where does glycolysis take place?
in the cytosol and does not require oxygen--also used in fermentation
121
net product of glycolysis
2 ATP
| 2 NADH
122
Pyruvate Manipulations
pyruvate dehydrogenase is the enzyme
1)Decarboxylation
-pyruvate moves from he cytosol into the mitochondrial matrix
-product one CO2
2)oxidation:
2 C molecule converted to acetyl group
-NAD+ to NADH
3)Acetyl CoA is produced
123
Krebs Cycle
Occurs in the mitochondrial matrix
-cytosol for prokaryotes
produces NADHx3
GTP
FADH2 linked to electron transport chain
124
Oxidative phosphorylation
ETC and chemiosmosis(ions moving down electrochemical gradient) work together to produce ATP
4 protein complexes-oxidation reduction (redox) reactions in ETC
- protons are pumped from the mitochondrial matrix to t he inter membrane space forming and electro chemical gradient
- INTERMEMBRANE=highly acidic
125
What is the final electron acceptor in oxidative phosphorylation?
Oxygen and gets reduced to water
126
ETC goal
- regenerate electron carriers
| - create an electro chemical gradient to power ATP production
127
Where does the ETC occur in eukaryotes and prokaryotes?
Mitochondrial inner membrane for eukaryotes
| Cell membrane-prokaryotes
128
ATP yield of aerobic cellular respiration?
exergonic; negative delta g
36-38 ATP
129
Fermentation
anaerobic pathway
- only relies on glycolysis
- convert pyruvate into lactate or ethanol to oxidize NADH back to NAD+; now glycolysis can continue
130
Cori cycle
used to help convert lactate back into glucose once oxygen is available agin
-transports lactate to liver cells and is oxidized to pyruvate
131
Obligate Aerobes
only perform aerobic respiration
| -neeed the presence of oxygen to survive
132
obligate anaerobes
only undergo anaerobic respiration or fermentation
| -oxygen poisens
133
Facultative anaerobes
can do:
aerobic respiration
anaerobic respirotn
or fermentation
prefers aerobic respiration, bc it generates more ATP
134
Microaerophiles
only perform aerobic respiration
| -high amounts of oxygen are harmful
135
Aerotolerant organisms
only undergo anaerobic respiration or fermentation
| -oxygen not poisonous to them
136
Adipocytes
cells that store fats
137
Proteins
least dersirable energy source (carbohydrates most desirable energy source)
138
Ammonia
toxic
| -must be converted into uric acid or urea
139
Heterotrophs
must get energy from the food they eat
140
autotrophs
can make their own food
141
Photoautotrophs
take light energy and convert it to chemical energy using photosynthesis
142
Photosynthesis
Creates chemical energy that is transferred through food chains
-reduces atmospheric CO2 and releases O2
Nonspontaneous
-prudcing glucose after an input of solar energy (photon)
143
Photons of light
| -in photosynthesis
used to synthesize sugars (glucose) in photosynthesis
144
Carbon fixation
process by which inorganic CO2 is converted into an organic molecule
-Photosynthesis takes
145
Where does the Calvin cycle occur?
Stroma
146
Where do light dependent reactions of photosynthesis occur?
Thylakoids
147
Light dependent reactions
use light energy to produce ATP and NADPH for later use I the Calvin cycle
148
Calvin Cycle
Also known as the light independent reaction
| -does not directly use light energy, but can only occur if the light dependent reactions are providing ATP and NADPH
149
Cell Cycle REgulation
prevents cancerous growth
1) Surface to Volume ration
- cell division occurs when Volume is to large
- decrease in S/V lead to division
2) Genome to volume ratio:
- decrease in G/V leads to division
- when volume is to large for cells to support its limited geneome
150
Steps of replication
1) initiation
- create origins of replication at A-T rich segments of DNA
2) elongation
- producing new DNA strand use different types of enzymes
3) termination
- replication fork cannot continue, ending DNA replication
151
Eukaryotic Post-transcriptional modificaiton
conversion of pre-mRNA into processed mRNA
1)5'capping
-protect the mRNA from degradation
2)Polyadenylation of the 3' end
-prevent degrdation by addition of Poly A tail
3) splicing out introns
-
152
Start Codon
AUG (Met)
153
Stop Codons
UAA, UAG, UGA
154
anticodon
group of three tRNA bases (A, U, G, or C) that base pairs with a codon
155
Aminoacyl-tRNA
tRNA bound to an amino acid
156
Aminoacyl-tRNA synthetase
enzyme that attaches an amino acid to a specific tRNA using the energy from ATp
157
3 methods of horizontal gene transfer in bacteria
1) conjugation
- use pili (cytoplasmic bridge)to copy and transfer a special plasmid known as F plasmid
- F+=bacteria contains an F plasmid
- F-= if bacteria doesn't contain
2) transformation
- bacteria take up extracellular DNA
- Competent bacteria-can perform transformation
3) Transduction
- viruses transfer bacterial DNA between different bacterial hosts
- occurs when bacteriophage enters the lysogenic cycle
158
Plasmids
circular DNA pieces that are independent from a bacterias singular circular chromosome
159
Haploinsufficiency
one of gene is lost or nonfunctional and the remaining copy is not sufficient for normal phenotype
160
haplosufficiency
when the remaining copy of the gene is SUFFICIENT for a normal phenotype
161
Proto-oncogenes
genes that can become oncogenes (cancer causing genes) due to gain of function mutations
-cause to much protein to be made or pruductin of an overactive protein
Follow one hit hypothesis
162
Tumor suppressor genes
genes that become cancerous as a result of loss-of function mutations
-normally need to suppress cancer growth
follow 2 hit hypothesis
HAPLOsufficient
163
p53
important tumor suppressor gene
Called-Guardian of the cell
-upregulated to prevent cell from becoming cancerous
164
p21
tumor suppressor gene
| -inhibits phosphorylation activity to decrease rampant cell division
165
Retinoblastoma gene (RB)
tumor suppressor gene
- codes for a retinoblastoma protein
- prevents excessive growth during interphase
166
Crossing over
creates genetic diversity
| -occurs during prophase 1 of meiosis
167
Karyotyping
observe chromosomes under light microscope during metaphase
168
Classifying organisms?
```
King Phillip Came Over For Great Soup
Kingdom
Phylum
Class
Order
Family
Genus
Species
```
169
6 kingdoms are?
Archaea
- Eubacteria
- Protista
- Fungi
- Animalia
170
Prokaryotes
Do not have a membrane bound nuclei and organelles
| Ex: eubacteria and Archaea
171
Eubacteria: Gram Positive vs Gram negative
Gram +
- thick peptidoglycan layer in cell wall
- stain dark purple
- no outer membrane
Gram -
- thin layer of peptidoglycan in cell wall
- stain pink
- contain outer membrane
BOTH:
-covered by a capsule
172
Eubacteria vs Arachea
```
Both:
contain cell walls
-70S ribosome
-DNA is organized in circular ploasmids (horizontal gene transfer via pilli)
-REPRODUCE VINARY FISSiion
```
Eubacteria:
- cell walls contain peptidoglycan
- ester linkage
- DNA lack introns and histones
Archaea
- cell wall lack peptidoglycan
- ether linkage
- contain introns comes have histones
173
Eukaryotes
contain membrane bound nuclei and organelles
| Ex: protista, fungi, plantae, and animalia
174
Protistata
unicellular eukaryotic organisms
175
Fungi
Heterotrophic saprophytes
1) Nonfilamentous (yeast)
- unicellular
- reproduce asexually by budding
- facultative anaerobes
2) filamentous fungi (molds)
- multicellular
- form hyphae
- reproduce sexually
- aerobic
176
Annelida
Earthworm
Bilateral body symmetry
closed circulatory system
177
Founder Effect
when a few individuals leave a larger population and settle in a new location
-individuals will have a smaller gene pool than their original population
GENETIC DIVERSITY DECREASED
178
Miller- Urey experiment on earth main conclusion
Organic molecules could form under the hypothesized conditions of early earth
179
An individual who is color-blind most likely has some deficiency in which part of the eye?
CONES
