Bio 101 Exam 3 Flashcards
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1
Q
Viruses
A
- infectious particles enclosed in protein coat (capsid)
-cellular parasites and have a specific host range
2
Q
Infectious particle
A
nucleic acid
3
Q
Capsid
A
- layer of proteins surrounding nucleic acid (virus genome- DNA or RNA)
- Some have a third layer- membrane phospholipid bilayer, called an envelope
4
Q
viral envelope
A
Surrounds virus protien - a lipid bilayer membrane formed by the host cell
5
Q
What can viruses infect
A
Plants, animals, people, and bacteria
6
Q
Glycoproteins
A
receptors
- Sticks out of viruses outermost layer
- Glycoprotein sometimes called receptor spikes
- Must bind to a host cell
-Each virus has specific spikes with special chemistry
-Viruses have specific receptors that must bind to the host cell for attachment entry
7
Q
Receptor spikes are on outside which lets them bump into host cells and bind
A
Triggers injection of DNA into host cell, capsid stays on outside
8
Q
Lactic cycle
A
when you are sick
9
Q
Lysogenic cycle
A
when you are sick, then goes dormant, then comes back
10
Q
Viruses use receptors to
A
bind to the host cell for attachment and entry
11
Q
A virus that has a dormancy phase
A
is able to integrate the genome of the virus into the host cell chromosome
the varicella-zoster virus infects many cells throughout the body and causes chickenpox, characterized by a rash of blisters covering the skin. About 10 to 12 days postinfection, the disease resolves and the virus goes dormant, living within nerve-cell ganglia for years.
12
Q
Can viruses have DNA and RNA
A
No, a virus cannot have both DNA and RNA; a virus can only contain one type of nucleic acid, either DNA or RNA, not both within the same viral particle.
13
Q
When a virus has an envelope (phospholipid bilayer, which is oil, which is liquid) it allows entry by fusion (instead of binding)
A
2 come together like merging oil droplets
14
Q
Reverse transcriptase
A
transcribes RNA into DNA
15
Q
Deoxyribonucleic acid
A
Deoxyribose (sugar)
■ Hereditary molecule that is passed from parents to offspring
■ Common to all living organisms
■ Sevres as the instruction manual for how to build an individual
■ Found i the nucleus of eukaryotic cells
- In the form of a chromosome ( Single DNA molecule wrapped around proteins)
16
Q
● What is DNA?
A
Deoxyribonucleic acid
17
Q
Why is each persons DNA different
A
- its structure to understand why
● Unique sequence of nucleotides, 4 different bases of nucleotides
● Each nucleotide has phosphate, sugar, and base
● Sugar backbone is sometimes drawn as a straight line with bases sticking off the sides
18
Q
What are nucleotides?
A
Monomers that combine to make DNA
19
Q
Nucleotides have one of four base
A
Adenine (A) ○ Thymine (T) Guanin (G) ○ Cytosine (C)
20
Q
What are the complementary base pairings for DNA?
A
○ A-T, C-G
Adenine will always pair with thymine and guanine will always pair with cytosine
21
Q
When referring to DNA, what is the “double helix”?
A
Two strands of linked nucleotides that are twisted around each other
22
Q
Two strands of nucleotides pair up and twist around each other to form a spiral shaped double helix
A
Sugars and phosphates form the outside “backbone” ○ Bases form the internal “rungs”
23
Q
Two strands of DNA double helix are held together by
A
base pairing ( hydrogen bonding ) between the bases of each stand
24
Q
● Complementary base pairing
A
A always pairs with T
C always pairs with G
25
DNA Replication
Natural process by which cells make an identical copy of a DNA molecule
- Takes advantage of complementary base-pairing rules
26
Helicase
can open up and separate two strands- breaks hydrogen bonds, binds to DNA, separates two strands of helix
27
DNA polymerase
enzyme that builds new DNA polymer
28
DNA replication is semiconservative
holds onto each side of the parent strand in the new daughter strands - half old, half new
29
Understanding the structure and replication of DNA is crucial to using it in forensic applications
Specific sequence of nucleotides along a strand of DNA is unique to each individual
- Extract the DNA from the cells to create individual's DNA profile (Visual representation of a person's unique DNA sequence) (Need many copies of their DNA)
30
The polymerase chain reaction (PCR)
PCR is a laboratory technique used to replicate and amplify specific DNA segment
31
Primers
short segments of DNA that guide DNA polymerase to the section of DNA to copy
32
During each round of PCR
1- Heating separates DNA strands
2- Cooling allows DNA polymerase to pair new nucleotides with the original template strands
- New DNA binds to template strand and builds complementary strand
33
● PCR test used when
you gave a small sample and want to increase sample size in order to test
34
PCR
heating, strand separation (double helix separates), DNA replication
35
PCR amplification of DNA is useful when
There is limited sample to work with
36
PCR can be useful in
DNA profiling
37
DNA profiling takes advantage of
the fact that no two people have the exact same DNA sequence
38
Genome
one complete set of genetic material present in a cell or organism
39
Determining sequence of entire genome is extremely time consuming and expensive
Use shortcut
- Use PCR to amplify only specific segments of DNA
○ Short tandem repeats (STR) ● STRs are sections of a chromosome in which DNA sequences are repeated
○ For example, sequence AGCT may be repeated over and over again
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What are short tandem repeats (STRs)?
Blocks of repeated DNA sequences (AGCT) that vary in length from person to person
41
STRs are in the same places along chromosomes
Exact length of STR varies from person to person
42
Making a DNA profile
- Collects cells and extract DNA
- Use PCR to amplify multiple STR regions
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Making a DNA profile– how will you visualize the results?
Separate STRs using gel electrophoresis
■ Laboratory technique that separates fragments of DNA by size
■ Small piece of DNA move fastest and go to the bottom, longer piece are slower and stay closer to the top
44
DNA evidence is
more reliable than other forms of evidence
○ Error rates for bite mark identification can be as high as 91%
○ Hair analysis can exclude a suspect, not positively identify one
45
no two people share exactly the same DNA except for...
identical twins
46
DNA in crime
Uses DNA as evidence to free people wrongly convicted of crimes
● DNA testing is a standard part of court cases
● Extremely accurate way to math crime scene evidence of perpetrators
47
When performing gel electrophoresis, STRs are separated
by pipetting them into a gel and applying an electric field, with the smallest fragments moving the furthest distance and the longest fragments moving the shortest distance, to create a unique profile of banding pattern for each individual
48
Sickle cell disease is an
nherited genetic disorder that causes red blood cells to take on a sickled shape (crescent moon) and carry less oxygen
49
Sickle cell disease
xperience anemia, episodes of severe pain, and other complications due to clots and blockages in blood vessels
● Sickle cells are less effective at carrying oxygen and can get stuck in vessels and veins and cause clots
50
How can we cure sickle cell anemia? (Treatments)
Treatments-
■ Narcotics for pain
■ Blood transfusions to provide normal red blood cells and reduce the concentration of sickle cells
■ Hydroxyurea medication to reduce the amount of sickling
51
How can we cure sickle cell anemia? (Cures)
Cures-
■ Bone marrow transplant
■ Gene therapy (NEW meth we are currently working on)
52
Cells in your kidneys produce different proteins and carry out different functions than cells in your brain. How is this possible?
Kidney and brain cells have the same DNA but use and express different genes
53
Every cell has same DNA, but they differ because they...
use regulatory regions to control timing, location, and amount of protein to express different genes
54
What are nucleotides?
Monomers found in DNA and RNA, Molecules made of a sugar, phosphate, and a base
55
When referring to DNA, what is the “double helix”?
Two strands of linked nucleotides that are twisted around each other
56
Two strands of linked nucleotides that are twisted around each other
Adenine will always [air with thymine and cytosine will always pair with guanine
57
What is DNA polymerase?
An enzyme involved in DNA replication that binds to DNA and synthesizes the new DNA strand
*ase=enzyme
58
When DNA is copied to make more DNA before a cell divides, what happens to the original (parent) DNA molecule?
Each of the cells contain DNA that is half original and half new DNA since DNA replication is semiconservative
59
PCR amplification of DNA is a useful technique when
There is limited sample
60
What are short tandem repeats (STRs)?
Blocks of repeated DNA sequences (AGCT) that are highly similar from person to person
61
A mutation in the gene for beta-globin results in new amino acid and sickling of red blood cells. What is the most likely outcome?
Reduced Oxygen Transport, Blockage of Blood Flow, Increased Hemolysis, Increased Risk of Infection
62
Genes
Are found on chromosomes, contain a regulatory region that controls when, where, and how much protein is made
63
What is a codon?
Three mRNA nucleotides that specify a particular amino acid
64
What is the complementary DNA sequence to GGCTATTACCG?
CCGATAATGGC
65
What is the RNA sequence to GGCTATTACCG?
CCGAUAAUGGC
66
RNA polymerase
Builds an mRNA polymer during translation
67
Viruses use receptors to
Bind to the host cell for attachment and entry
68
The job of tRNA is to
Use the anticodon to bring the right amino acid to the ribosome
69
Ribosomes
Bind the mRNA and catalyze formation of the bonds between amino acids
70
mRNA
Carry the codon information from the nucleus to the ribosome
71
Gene therapy can use viruses to
Deliver new genes to cells and alleviate the effects of certain genetic disorders
72
What is a transgenic organism?
An organism that contains genes from a different species
73
A virus that has a dormancy phase
Is able to integrate the genome of the virus into the host cell chromosome
74
What type of mutation causes one new amino acid to be in a protein?
Missense
75
What type of mutation causes an early stop codon and truncation of the protein?
Nonsense
76
Approximately what percentage of the human genome consists of noncoding DNA?
98%
77
Which of the following is not a function of mitosis in humans?
Production of gametes from diploid cells
78
The following karyotype shown below is likely from an individual with
Down Syndrome (extra chromosome)
79
What is the ultimate source of all diversity?
Mutation
80
How many nucleotides make up a codon?
Three
81
If adenine makes up 35% of the bases in a DNA double helix, what percent of the bases would you expect to be guanine? (Hint this question requires careful examination and consideration of Chargaff's rule)
15%
82
______ takes place in the nucleus and _______ require(s) rRNA.
Transcription; translation
83
84
The process of DNA replication requires
breaking of hydrogen bonds, unwinding of the DNA, enzymes, nucleotides (all of the above)
85
PCR amplification of DNA is a useful technique when
There is limited sample
85
Consider the following figure. It indicates that a single amino acid substitution _____.
May alter a protein so that it no longer functions properly
86
A diploid alien that reproduces via sexual reproduction and meiosis has 32 chromosomes. How many chromosomes are in each of its haploid gametes?
16
87
The data that showed that DNA is a helix in its "wet form" was collected by______.
Rosalind Franklin
87
Which of the following best describes the pattern of increasing copies of DNA during PCR amplification?
1 -> 2 -> 4 -> 8
88
Most chemotherapy drugs are effective because they
Interrupt cell division
89
The overall three-dimensional shape of a protein molecule is determined by
the order of amino acids and how it folds up
90
What determines a protein's functionality?
the three dimensional shape of the folded protein
91
All proteins begin with the amino acid
methionine (met)
92
A mutation in the gene encoding for head coaching success in college football results in a protein with a
drastically distorted three-dimensional shape. What is the most likely outcome?
The success protein will not function properly
93
Alleles are alternative versions of _____________ genes(s) that have ________nucleotide sequences.
The same; small differences in their
94
Which of the following is the best definition for recombinant DNA?
DNA that includes pieces from two different sources
95
Your DNA is
Identical in all cells
96
Chromosomes that do not determine the sex of an individual are called ______.
Autosomes
97
Which short tandem repeat would likely migrate the least distance through an electrophoresis gel?
GAAGC repeated four times
98
An epigenetic change in gene expression is a change that does not involve any change in nucleotide sequence
of the gene.
TRUE
99
The expressed (coding) regions of eukaryotic genes are called ______.
Exons
100
After a bad sunburn skin usually peels off at an accelerated rate. What process best describes what has happened to the burned skin cells?
Apoptosis
101
A woman
with a BRCA1 mutation
Is at an increased risk of developing breast cancer
102
A mutation would most likely be inherited if it is located in a ____ cell
Sperm
103
Which of these typically does NOT directly cause cancer?
Inherited Mutations
104
The final product of gene expression is
A protein
105
Two daughter strands of DNA are synthesized during replication. Which term best describes the new chain of DNA that begins at the origin of replication (fork) and is synthesized continuously in the direction of replication.
Leading Strand
106
Since DNA is replicated semiconservatively, what does each new daughter cell receive from the parent cell
after replication and mitosis?
One of the original strands and one new strand
107
If two individuals were both heterozygous for freaky toad warts, which are a dominant trait, what percentage of their progeny would have freaky toad warts?
75%
108
Which enzyme is used to bind DNA fragments together?
DNA Ligase
109
DNA replication occurs during which phase of the cell cycle?
Interphase
110
Gel electrophoresis separates DNA fragments on the basis of differences in their ______.
Length
111
Why might radiation therapy increase the risk of cancer reoccurring?
exposure to radiation can damage DNA of normal cells, which can contribute to cancer
112
Which enzyme pairs corresponding nucleotides to a preexisting DNA chain in order to synthesize a new strand of DNA?
DNA Polymerase
113
A cell spends most of its time in
Interphase
114
An anticodon is a sequence of three nucleotides that _________________.
is found on transfer RNA and is complementary to messenger RNA codons
115
Cancer is
unregulated cell division
116
Reference the codon table, at the end of your assessment packet for this question. The anticodon sequence UUC codes for the amino acid ______.
Lysine
116
What is the difference between eukaryotic and prokaryotic gene transcription?
In eukaryotes it occurs in the nucleus; in prokaryotes it occurs in the cytoplasm.
117
Which of the following can cause cancer to develop and progress?
an oncogene and a mutated tumor suppressor genw
