Biology 112 Final Test Flashcards
(142 cards)
1
Q
What are the phases of the Eukaryotic Cell Cycle?
A
G1, G2, S, M
2
Q
How much time does it take for the whole eukaryotic cell cycle?
A
24 hours
3
Q
What is G1 and G2 phases of the cell cycle?
A
Gap phases
4
Q
What is the S phase of the cell cycle?
A
DNA replication
5
Q
How long does it take for S phase to do its job?
A
10 hours
6
Q
What is the M phase in cell division?
A
Mitosis
7
Q
How long does it take for M phase to do its job?
A
1 hour
8
Q
What are the two big overall steps of DNA replication?
A
1) 2 parent strands are separated
2) Each parent strand is used as a TEMPLATE
9
Q
In the first step of DNA replication, what is broken?
A
hydrogen bonds
10
Q
How is DNA replication not transcription?
A
- more than 1 protein copied
- process is not to synthesize mRNA
- its semi-conservative`
11
Q
Where does DNA replication begin?
A
origins of replication
12
Q
Which direction does DNA proceed?
A
bidirectionally from the origin
13
Q
How many start points are on each chromosome?
A
thousands
14
Q
How many bases are needed each time the cell divides?
A
6 billion
15
Q
What is a plasmid?
A
circular piece of DNA commonly found in bacteria
16
Q
What is the rate of replication?
A
2000bp/minute (30ish per second)
17
Q
How long would it take if there was only one origin of replication?
A
1 month
18
Q
Why are origins of replication AT rich?
A
2 hydrogen bonds break easier than 3 of GC
19
Q
What is ORC?
A
multi-subunit protein that binds at Origin to initiate replication
20
Q
Which cells in the body are always replicating because of mechanical stress?
A
epithelial
21
Q
What are enzymes that catalyze DNA replication?
A
DNA polymerases
22
Q
Which direction of DNA does DNA polymerase work?
A
5’ to 3’
23
Q
What is the problem of the direction DNA polymerase works?
A
DNA has two strands that are opposite directions
24
Q
What is the strand that is made 5’ to 3’ called?
A
leading strand
25
What is the strand made 3' to 5' called?
lagging strand
26
How is the lagging strand made?
In fragments
27
DNA is not straight but spiral, what does this cause?
mechanical stress further down
28
What works to relieve the stress?
topoisomerase (gyrase)
29
How does the topoisomerase work?
Knicks/cuts one of two strands, unravel, then reconnect
30
What is a ligase?
an enzyme that will link okazaki fragments together
31
DNA Polymerases make mistakes...if not fixed what would happen
DNA would have mutations forever
32
What is the process of removing incorrect base and putting in correct base called?
proofreading
33
What are single stranded DNA binding proteins function?
single strand of DNA is susceptible and unstable and SSB gives protection and stability till nucleotides bond
34
What comes in to make short pieces of RNA to get DNA replication started?
primase
35
What binds the lagging strand parts?
ligase
36
What are ways DNA can be damaged?
carcinogens
37
What are carcinogens?
cancer causing agents
38
What is the process of DNA excision and repair?
1) enzymes recognize damage
2) damage is removed
3) Polymerase can fill in
4) DNA ligase does the rest
39
What is the outcome/ product of mitosis?
two identical daughter cells
40
What are the four stages of mitosis?
1) prophase
2) metaphase
3) anaphase
4) telophase
41
What happens in prophase?
- chromosomes condense
- centrosomes migrate
- mitotic spindle forms
- nuclear membrane fragments
42
What do chromosomes condense into?
compact fibers that are extensively folded
43
What forms the mitotic spindle?
microtubules from the centrosomes
44
What is the Kinetochore?
a protein complex attached to the chromosomes at centromere
45
What is Metaphase?
the point where prophase has occurred and chromosomes have been lined up but not yet separated
46
What is the metaphase plate?
the imaginary plane that is equidistant from the 2 poles of the spindle in which the chromosomes line up upon
47
When are chromosomes analyzed in lab?
metaphase
48
What occurs in anaphase?
sister chromatids are separated
49
How are the chromatids pulled?
microtubules getting shorter and shorter
50
What causes the microtubules to get shorter?
Small Motor proteins removing tubulin subunits from the microtubules
51
What is telophase?
the rebuilding of the cells
52
What is the final step in cell division?
cytokinesis
53
What is a contractile ring composed of?
actin and myosin
54
What is the product of meiosis?
four cells that ONLY contain one copy of each pair of homologous chromosomes
55
What are haploid cells?
only contain one pair of homologous chromosomes
56
What are homologous chromosomes?
similar but not exactly identical
57
What are alleles?
variations in genes
58
What are somatic cells?
non-germ cells, diploid, contain 46 chromosomes
59
What are germ cells?
haploid and contain only one set of chromosomes
60
How do haploid cells result in diploid state?
fertilization
61
How are Gametes formed?
process of meiosis
62
How many nuclear divisions are in meiosis?
two
63
How many daughter cells result of meiosis?
4
64
Are the 4 daughter cells of meiosis identical?
No, they are each genetically different
65
What is the key of meiosis?
homologous pairs line up in pairs and during 1st division sister chromatids stay together
66
What is the four stranded structure produced in lining of homologous chromosomes?
bivalent
67
What occurs in the first division during Meiosis I?
homologous chromosomes are separated from each other and two cells are formed
68
What occurs in the second division during Meiosis II?
The sister chromatids line up and are separated resulting in 4 cells of 23 chromosomes
69
What occurs in meiosis that lends towards more genetic diversity?
chromatids of homologous chromosomes exchange DNA
70
Why is only one egg formed in female?
uneven distribution of cytopasm results in only one function
71
What is the probability of conceiving genetically identical children?
1 in 64 trillion
72
Why do cells need to communicate with each other?
behavior of cells throughout body should be coordinated
73
What do cells make up that affect communication?
cells make up tissues that make up organs that then should be regulated by cell activity
74
What is one thing, other than organelles, that each cell has?
genome
75
What is genome?
have all genes/DNA
76
Are all genomes expressed?
No, only the genes needed for function of the cells
77
What is gene expression regulated by?
transcription factors
78
What is a huge end result of expression and communication?
regulation of genes
79
What are transcription factors often regulated by?
signaling pathways
80
What does signaling pathway ultimately end with?
signaling factors
81
What is apoptosis?
No signaling or a signal tells it to go away, DNA self destruction
82
What is the process of signaling?
1) receptor-ligand binding
2) signal transuction
3) cellular responses
4) changes in gene expression
83
Are the receptors specific or general?
specific to protein
84
What does it mean that signal transduction pathways can amplify?
the cell pathways are not 1:1 and amplify and activate other cells so the signal gets bigger and bigger
85
What are the two types of signaling
Homonal
| Local mediators
86
What is homone signaling?
distant cell that binds to a target cell at some distance away
87
What is local mediator signaling?
cell is communicating with the cells adjacent or close to it
| ex: nervous system
88
What types of cells can pass through a membrane and directly bind to intracellular targets?
steroids
89
What are the two types of cell-surface receptors?
1) G-protein linked
| 2) enzyme-linked recptors
90
What is the g stand for in g linked receptors?
guanine
91
What is the largest class of cell-surface receptors?
g-protein
92
What type of cells is g-protein found?
eukaryotes
93
What do G-protein linked receptors consist of?
single polypeptide chains
| 7-membrane spanning domains
94
What is the function of G-protein linked receptors?
binding of signal molecule causes conformational change activates a G-protein
95
What are G-proteins?
GTPases
96
How is the inactivated binded GDP activated?
when it binds GTP it releases alpha unit and becomes activated that can activate other proteins
97
Is the signal of G-protein temporary or lasting?
temporary
98
What ends the signal of G-protein?
GTPase breaks down to GDP which ends signaling pathway
99
What is enzyme linked receptors?
single-pass transmembrane proteins
100
What is the function of enzyme-linked receptors?
bind signal molecules
101
How fast is the enzyme linked receptor?
slow (hours)
102
Cystosolic domain is either an enzyme itself OR associated directly with an enzyme...
INFO
103
Receptor Tyrosine Kinases outside function.
binding receptor inside= phosphorylating things
104
How are receptor tyrosine kinases activated?
dimerization following binding of signaling molecule
105
what is autophosphorylation?
monomers phosphorylate each other
106
What do phosphorylated tyrosines serve as?
binding sites for other signaling proteins
107
What is carcinoma?
cancers arising from epithelial cells
108
Why is epithelial most common?
deal with most mechanical stress and need duplication the most
109
What are 2 main characteristics of cancer cells?
1) uncontrolled growth
| 2) ability to spread
110
What are 6 results of uncontrolled growth?
1) anchorage independent growth
2) lose contact inhibition
3) abnormalities in signaling pathways
4) disruptions in cell cycle control
5) block of apoptosis
6) balance of replication/differentiation is shifted
111
What is apoptosis?
programmed cell death
112
Does cancer occur at one mutation?
No, it is the accumulation of mutations over a lifetime
113
What occurs when balance of differentiation is disrupted?
tumors occur, build up of cells
114
Why does apoptosis occur?
health of entire organism is more important than any single cell
115
What are two forms of cell death?
1) apoptosis
| 2) necrosis
116
What is necrosis?
cell bursts and contents spill out
117
How does necrosis result?
1) injury
| 2) inflammatory response
118
How does apoptosis process occur?
1) cell condenses and shrinks
2) cell surface changes to cause endocytosis by macrophage
3) chromosomal DNA is cleaved
119
How does apoptosis and cancer relate?
If process is mutated
120
What is the difference between benign and malignant tumors?
ability to spread
121
What is a benign tumor?
single mass of cells that have not invaded surrounding tissue
122
What is malignant tumor?
cells have acquired ability to invade surrounding tissue
123
What is metastases?
cells can break off from primary tumor, enter the bloodstream, and form secondary tumors at other sites
124
For the ability to spread what do tumors need?
Angiogenesis
Invasion
Metastasis
125
What is angiogenesis?
new blood vessel formation
126
Without angiogenesis how large can tumors grow?
1-2mm
127
What initiates angiogenesis?
VEGF to bind to blood vessels and initiate growth
128
What is invasion?
direct migration into neighboring tissues
129
What do cancer cells release that destroys protein barrier?
proteases enzymes
130
Where do cancers metastasize/ why?
Lymph nodes: before entering bloodstream, many cancer cells enter lymphatic vessels and are carried to lymph nodes to blood stream
131
Once tumors in bloodstream where do they usually go?
Lungs: tumors in most organs encounter capillary bed of the lungs when they enter blood stream
Liver: cancers arising in stomach and colon cells enter the liver shortly after entering bloodstream
132
What are the two factors that cause cancer?
Hereditary
| Environmental
133
What are chemicals that cause cancer called?
carcinogens
134
What do carcinogens often cause?
DNA mutations
135
What other factors cause DNA mutations?
UV light and radiation, viruses
136
How many mutations are needed in order for a cell to be cancerous?
6-10 mutations
137
What two specific genes are mutated by carcinogens and radiation?
1) Oncogenes
| 2) tumor suppressors
138
What are oncogenes?
tell the cell when to duplicate and promote growth in cells under normal circumstances
139
What are tumor suppressors?
tells the genes when to stop duplication
140
What occurs when oncogenes are expressed at higher levels?
cancer, over growth of cell
141
What occurs when tumor suppressors lose function of being turned off or non-functional?
cancer
142
What is chemotherapy?
anti-cancer drugs that kill rapidly growing cells
