Exam 3 Flashcards
(115 cards)
1
Q
4 events of cell division
A
- Extra/internal signals initiate cell division
- Cells must have a full set of genetic info during DNA replication
- Each daughter cell receives a full copy of all chromosomes during DNA segregation
- Cytokinesis (division of cytoplasm to form membranes)
2
Q
Cell division signals- prokaryote v eukaryote
A
Prokaryotes- external factors tells cell to reproduce
Eukaryotes- division related to function of body
3
Q
Chromosomes- prokaryotes v eukaryotes
A
Prokaryotes- 1 main chromosome
Eukaryotes- multiple chromosomes
4
Q
DNA segregation- prokaryotes v eukaryotes
A
Prokaryotes- Cells move to one side
Eukaryotes- mitosis separates chromatids into 2 nuclei
5
Q
Cytokinesis- prokaryotes v eukaryotes
A
Prokaryotes- new cell wall materials are deposited
Eukaryotes- plant cells have cell wall and animal cells have no cell wall
6
Q
What is the cell cycle
A
Interphase, mitosis and cytokinesis
7
Q
What happens during interphase
A
The cell is doing its work; nucleus is visible
8
Q
What are the subphases of interphase
A
G1, S phase, and G2
9
Q
G1
A
Chromosomes are single
10
Q
R-point
A
Initiation spot of cell division, committing to replication (r point= replication point)
11
Q
S Phase
A
DNA replication
12
Q
G2
A
Cell prepping for mitosis
13
Q
M phase
A
Mitosis and cytokinesis
14
Q
Cyclin- dependent kinases
A
DNA checkpoints to make sure there’s no damage
15
Q
Mitosis
A
Division of the nucleus; prophase, metaphase, anaphase, telophase
16
Q
Homologous pair
A
Matching chromosomes made of each set (same length and shape)
17
Q
Sister chromatid
A
Identical DNA, replicated chromosomes
18
Q
Chromatin
A
Protein involved in replication and transcription
19
Q
Cohesion
A
Protein that regulates separation of sisters; gone by the end of metaphase (keeps sisters together until they are able to separate)
20
Q
Centromere
A
Region where sisters join
21
Q
Histones
A
Packages and orders DNA
22
Q
Spindle apparatus
A
Microtubules that help move the chromosomes
23
Q
Centrosome
A
Poles where chromosomes go during separation
24
Q
Prophase
A
Nucleus breaks down, sisters condense, spindles form
25
Metaphase
Chromatids line up in middle of cell
26
Prophase
Spindles pull sisters apart
27
Telophase
Membrane is reassembled around chromosmes
28
# of parent- sexual v asexual
Sexual- 2
Asexual- 1
29
Gametes- sexual v asexual
Sexual- yes
Asexual- no
30
Fertilization- sexual v asexual
Sexual- yes
Asexual- no
31
# of chromosomes- sexual v asexual
Sexual- 2
Asexual- 1
32
Type of cell division- sexual v asexual
Sexual- meiosis
Asexual- mitosis
33
Asexual reproduction
Based on mitosis
Off-spring from a single parent
Genetically identical
Clones
34
Sexual reproduction
Requires 2 parents to create genetically unique off-spring
Not identical
35
Fertilization
2 haploid gametes fuse to form diploid (zygote)
36
How many rounds of division are in meiosis v mitosis
Meiosis- 2 (46 chromosomes)
Mitosis-1 (23 chromosomes)
37
Difference in 2 rounds of meiosis
Round 1- homologous pairs separate
Round 2 sisters separate
38
How many gametes does meiosis produce
4 haploid gametes
Genetically unique daughter ccells
39
Crossing over
Exchanging of genetic info between 2 non-sister chromatids
Provides genetic diversity
40
Necrosis
Premature cell death
Cell swells and bursts
Mechanical means or toxins, starved of oxygen or nutrients
41
Apoptosis
Programmed cell death
Cell may no longer be needed
42
Benign tumor
Reassemble the tissue they come from
Not cancerous
43
Malignant tumor
Does not resemble parent tissue
Cancerous
Can move and grow in other parts of the body
44
What are the 2 regulatory systems of cell division
Oncogene protein: gas petal, tells cells to grow
Tumor suppressors: brakes, stops cells from growing, not in cancer cells
45
Hereditary
Passing of characteristics genetically
46
2 hypothesis of breeding results
Blending inheritance: genes blend to zygote
Particulate inheritance: genes are distinct
47
Characteristic
Observable physical feature
48
Trait
Form of character
49
Gene
Unit of heredity
50
Allele
Different version of genes
51
Locus
Specfic place on chromosome
52
Homozygous
Having identical alleles of a given gene
53
Heterozygous
Different alleles of a given gene
54
Genotype
Exact description of genetic makeup
55
Phenotype
Observable properties
Relates to genotype
56
Diploid
Having 2 copies of a gene
57
Haploid
A single copy of each gene
58
Mutation
Change in genetic makeup
59
Wild-type
Allele that is in most people
60
Recombinant
Chromosome in which genetic material comes from 2 individuals in the same haploid gene
61
Sex chromosomes
Female- XX
male- XY
62
Conjugation
How bacteria exchange genes
63
Function of plasmids in bacteria
Metabolic function
Antibiotic resistant genes
Genes for reproduction
Exchanged during conjunction
64
What is DNA made of
Deoxyribose, phosphate group, nitrogenous base
65
What are the 4 bases
Purines: adenine and guanine (2 rings)
Pyrimidines: cytosine and thymine (1 ring)
66
What are the base pairs
Adenine and thymine
Cytosine and guanine
67
Nucleotide backbone
Made from a phosphate and helps keep its shape
68
4 key features of DNA structure
1. Double helix
2. Right-handed helix
3. Anti parallel strands
4. Major and minor groves
69
Double helix
Phosphate backbone and bases in center
70
What bonds are between the bases
Hydrogen bonds
71
Why is double helix important to DNA
Variations in sequences account for differences between species
72
Semiconservitive
How DNA is replicated; 1/2 of the molecule is from original DNA strand and other 1/2 is new
73
3 steps in DNA replication
1. Initiation: double helix is unwound
2. Elongation: nucleotides form complementary bases with template
3. Termination: DNA synthesis ends; 2 stands of DNA
74
DNA helicase
Unwinds DNA double helix
75
Single-stranded binding proteins
Binds to help keep 2 strands of DNA separate during replication
76
DNA primase
RNA primer (starting point, complementary to DNA)
77
DNA polymerase
Linking nucleotides together and removes primer
78
DNA ligase
Connect Okazaki fragments to on another
79
Where does DNA replication start
The origin of replication (ori)
80
leading strand v lagging strand
Leading strand grows at 3’ end
Lagging strand has Okazaki fragments (fragments of nucleotides)
81
Telomeres
Repeated DNA sequences at end of chromosomes
Prevents DNA repair system from recognizing end of chromosomes
82
How does DNA change
DNA polymerase makes mistakes in assembling the nucleotide strands
chemicals, UV radiation and other threats
83
Cells repair mechanisms
Proofreading: DNA polymerase makes sure bases match
Mismatch repair: new DNA is scanner for mismatching pairs
Excision repair: damaged nucleotides are removed and replaced with new ones
84
Polymerase chain reaction (PCR)
Raid production of DNA to help with lab work
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One-gene, one polypeptide relationship
Each gene corresponds with one polypeptide
86
2 steps of gene expression
Transcription and translation
87
Transcription
DNA sequence being arranged differently for RNA to read
88
Translation
RNA sequence being used to make polypeptide chains
89
3 types of RNA
mRNA (messenger RNA)
tRNA (transfer RNA)
rRNA (ribosomal RNA)
90
How is RNA differnet from DNA
RNA uses uracil instead of thymine
RNA uses ribose instead of deoxyribose
91
Components of transcription
1 DNA strand to use as template
4 ribonucleocide triphosphates (ATP, GTP, UTP, CTP)
RNA polymerase enzyme
92
What do all RNA polymerase share
Catalyze the synthesis of RNA
Share common structure
Build in 5’ to 3’ direction
Don’t need a primer (DNA polymerase needs primer)
93
Steps in RNA transcription
1. Initiation: promoter initiates transcription
2. Elongation: RNA polymerase reads DNA in 3’ to 5’ direction. Builds by adding nucleoside triphosphates in the 5’ to 3’ direction
3. Termination: RNA polymerase reaches termination site, polymerase and RNA sequence is released
94
Precursor mRNA
First transcript, needs to be modified
95
Introns
Part of gene that’s transcribes, but sliced out
96
Exon
Presented in mature RNA
97
mRNA processing
Modifying transcript before leaving the nucleus
98
5’ cap
Added on 5’ end to protect mRNA from being broken down
99
Poly A tail
Added to 3’ end to allow mRNA recognition
100
RNA splicing
Last step in mRNA processing where the introns are removed
101
Genetic code
Specifies what amino acid will be used to build a protein
AAG (3 letters)
Universal
102
Start codon
Initiation site for translation (AUG)
103
Stop (nonsense) codon
Termination site (UAA, UAG, UGG)
104
Sense codons
61 codons can “spell” 20 amino acids
105
Functions of tRNA
Bind to particular amino acids
Bind to mRNA
Interacts with ribosomes
106
What bond forms between amino acids
Polypeptide bond
107
When is tRNA charged
When it is bonded to an amino acid
108
What does the ribosome do
Holds mRNA and charged tRNA to allow polypeptide chain to form
Can make any type of protein, gets used over and over agin
109
3 sites tRNA can bond to
1. A site: charged tRNA anticodon bonds to mRNA codon
2. P site: tRNA adds amino acids to polypeptide chain
3. E site: uncharged tRNA is released into cytoplasm to be used over again
110
Fidelity function
Hydrogen bonds between bases between mRNA codon and tRNA anticodon (double checking)
111
3 steps of translation
1. Initiation: charged tRNA bonds to start codon in
2. Elongation: tRNA is A site, bond between tRNA and amino acid is broken and steps repeat (protein synthesis )
3. Termination: when stop codon enters A site; everything is released including polypeptide chain and protein release factor
112
Signal sequence
Added to polypeptide chain to show it where it goes
113
Proteolysis
Polypeptide is cut by enzyme proteasase
114
Glycoslyation
Glucose is adde to polypeptide chain to make glycoproteins
115
Phosphorylation
Addition of phosphate groups to polypeptide chain
