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Bio > UNIT 6 ck12’s 4.8-4.13 > Flashcards

UNIT 6 ck12’s 4.8-4.13 Flashcards

1
Q

What is a mutation?

A

A change in the sequence of bases in DNA

Mutations can occur in any organism and are a natural part of genetic variation.

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2
Q

Do most people have mutations in their DNA?

A

Yes, most people have dozens or even hundreds of mutations in their DNA

These mutations are a common aspect of human genetics.

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3
Q

What role do mutations play in evolution?

A

Mutations are essential for evolution to occur

They provide the genetic variation necessary for natural selection.

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4
Q

What are the ultimate sources of new genetic material in a species?

A

Mutations are the ultimate source of all new genetic material - new alleles

This genetic variation is crucial for a species’ adaptation and evolution.

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5
Q

Do most mutations have an effect on organisms?

A

Most mutations have no effect on the organisms in which they occur

Many mutations are neutral and do not influence survival or reproduction.

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6
Q

Can mutations be beneficial?

A

Yes, some mutations are beneficial

Beneficial mutations can enhance an organism’s fitness in its environment.

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7
Q

True or False: Harmful mutations always cause drastic changes in organisms.

A

False

Even harmful mutations rarely cause drastic changes, and many may have subtle effects.

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8
Q

What are the two major categories of mutations?

A

Germline mutations and somatic mutations

Germline mutations occur in gametes, while somatic mutations occur in other body cells.

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9
Q

What happens to germline mutations in offspring?

A

They can be transmitted to offspring, affecting every cell in the offspring

This means that the mutation is present in the genetic material passed down.

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10
Q

What are somatic mutations?

A

Mutations that occur in other cells of the body, confined to one cell and its daughter cells

Somatic mutations cannot be passed on to offspring.

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11
Q

What are the two main ways mutations can change genetic material?

A

Change the structure of a chromosome or change a single nucleotide

This indicates the different scales at which mutations can occur.

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12
Q

What are chromosomal alterations?

A

Mutations that change chromosome structure

They occur when sections of a chromosome break off and rejoin incorrectly or do not rejoin.

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13
Q

What is deletion in the context of chromosomal alterations?

A

When a segment of DNA is lost, resulting in a missing segment in the chromosome

This usually leads to many genes missing from the chromosome.

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14
Q

What does duplication mean in chromosomal alterations?

A

When a segment of DNA is repeated, creating a longer chromosome

This typically results in multiple copies of genes in the chromosome.

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15
Q

Define inversion in chromosomal alterations.

A

When a segment of DNA is flipped and then reattached to the same chromosome

This can affect gene expression and function.

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16
Q

What is insertion in the context of chromosomal alterations?

A

When a segment of DNA from one chromosome is added to another, unrelated chromosome

This can lead to genetic disorders or changes in gene function.

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17
Q

What is translocation in chromosomal alterations?

A

When two segments from different chromosomes change positions

This can result in gene fusion and may cause various diseases.

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18
Q

What is a point mutation?

A

A change in a single nucleotide in DNA.

Point mutations are usually less serious than chromosomal alterations.

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19
Q

What is an example of a point mutation?

A

A mutation that changes the codon UUU to the codon UCU.

This illustrates how a single nucleotide change can alter the genetic code.

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20
Q

What are the three types of point mutations?

A
  • Silent
  • Missense
  • Nonsense

These types of mutations are also known as substitutions.

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21
Q

What is a silent mutation?

A

A mutated codon that codes for the same amino acid.

Example: CAA (glutamine) changes to CAG (glutamine) with no effect on the protein.

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22
Q

What is a missense mutation?

A

A mutated codon that codes for a different amino acid.

Example: CAA (glutamine) changes to CCA (proline), leading to variable effects.

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23
Q

What is a nonsense mutation?

A

A mutated codon that is a premature stop codon.

Example: CAA (glutamine) changes to UAA (stop), which is usually serious.

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24
Q

What is a frameshift mutation?

A

A type of point mutation that includes a deletion or insertion of one or more nucleotides, changing the reading frame.

This significantly alters how the codons are read.

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25
What effect does a frameshift mutation have on protein synthesis?
It can dramatically change how the codons in mRNA are read, affecting the protein product. ## Footnote Even a single nucleotide insertion can change the entire sequence of amino acids.
26
Fill in the blank: A frameshift mutation can occur due to _______ or insertion of nucleotides.
deletion ## Footnote Deletions remove nucleotides from the sequence.
27
What happens to the reading frame of RNA during a frameshift mutation?
It changes, affecting all following codons. ## Footnote For example, inserting an A after the start codon changes subsequent amino acids.
28
What is albinism?
Albinism is a condition characterized by a lack of pigmentation in organisms.
29
Why is albinism not commonly seen in nature?
The change in pigmentation is often a disadvantage to organisms in their natural environment.
30
How does albinism affect an organism's vulnerability?
The lack of pigmentation can make the albino organism more vulnerable and an easier target to predators.
31
What is one example of an organism affected by albinism?
An example is an albino alligator.
32
Fill in the blank: Organisms with albinism cannot easily _______ themselves into their environment.
[camouflage]
33
What is a consequence of being an albino organism regarding survival?
An albino organism may not live long enough to survive and reproduce.
34
True or False: Albinism provides a survival advantage in natural environments.
False
35
What are the two main categories of causes for mutations?
Spontaneous mutations and mutations caused by environmental factors. ## Footnote Spontaneous mutations occur without outside influence, while environmental factors involve mutagens.
36
What is a mutagen?
Anything in the environment that can cause a mutation. ## Footnote Mutagens can include chemicals, radiation, and other environmental influences.
37
What can cause spontaneous mutations?
Mistakes made during DNA replication or transcription. ## Footnote These errors can occur naturally and do not require external factors.
38
True or False: All mutations are caused by external factors.
False. ## Footnote Some mutations occur spontaneously without any external influence.
39
Fill in the blank: Mutations can occur when mistakes are made during _______ or _______.
DNA replication; transcription. ## Footnote These processes are critical for cell division and gene expression.
40
What are the five common types of spontaneous mutations?
1. Tautomerism 2. Depurination 3. Deamination 4. Transition 5. Transversion ## Footnote Each type represents a different mechanism by which mutations can occur spontaneously.
41
Define tautomerism in the context of spontaneous mutations.
A base is changed by the repositioning of a hydrogen atom. ## Footnote This process can lead to incorrect base pairing during DNA replication.
42
What is depurination?
Loss of a purine base (A or G). ## Footnote This type of mutation can result in the formation of apurinic sites in DNA.
43
What does deamination refer to?
Spontaneous deamination of 5-methylcytosine. ## Footnote Deamination can lead to the conversion of cytosine to uracil, which can cause mispairing.
44
What is a transition mutation?
A purine to purine (A to G, G to A), or a pyrimidine to pyrimidine (C to T, T to C) change. ## Footnote Transition mutations are generally more common than transversions.
45
Define transversion mutation.
A purine becomes a pyrimidine, or vice versa. ## Footnote Transversions are less common than transitions and can lead to more significant changes in DNA.
46
What is the result of a mutation in the context of the mouse?
A change in the DNA sequence. ## Footnote This specific mutation resulted in the mouse being hairless.
47
What are the possible effects of mutations?
They can be beneficial, have no effect, or have lethal consequences. ## Footnote Every possibility exists between these extremes.
48
What are neutral mutations?
Mutations that have neither negative nor positive effects on the organism. ## Footnote Examples include silent point mutations.
49
Why are silent point mutations considered neutral?
They do not change the amino acids in the proteins they encode.
50
What happens to many mutations before protein synthesis occurs?
They are repaired by the cell.
51
What mechanisms do cells have to handle DNA mutations?
Multiple repair mechanisms to fix mutations.
52
What occurs if a cell's DNA is permanently damaged?
The cell is likely to be prevented from dividing.
53
What are mutations that have a positive effect on organisms called?
Beneficial mutations ## Footnote Beneficial mutations help organisms adapt to environmental changes and are essential for evolution.
54
What do beneficial mutations lead to in proteins?
New versions of proteins ## Footnote These new versions help organisms adapt to changes in their environment.
55
How do beneficial mutations affect an organism's chances of survival?
Increase chances of surviving or reproducing ## Footnote This likelihood leads to beneficial mutations becoming more common over time.
56
Name an example of a beneficial mutation in bacteria.
Mutations that allow survival in the presence of antibiotic drugs ## Footnote These mutations result in antibiotic-resistant strains of bacteria.
57
What is a unique mutation found in a small town in Italy known for?
Protecting from developing atherosclerosis ## Footnote Atherosclerosis is the dangerous buildup of fatty materials in blood vessels.
58
What analogy is used to describe harmful mutations?
Making a random change in a complicated machine like a car engine ## Footnote Random changes in genes are likely to result in harmful effects, similar to a poorly functioning car.
59
What is a genetic disorder?
A disease caused by a mutation in one or a few genes ## Footnote An example is cystic fibrosis, which is caused by a mutation in a single gene.
60
What does cystic fibrosis cause the body to produce?
Thick, sticky mucus ## Footnote This mucus clogs the lungs and blocks ducts in digestive organs.
61
What is cancer generally caused by?
Mutations in genes that regulate the cell cycle ## Footnote These mutations allow cells with damaged DNA to divide without limits.
62
True or False: Harmful mutations can lead to cancer.
True ## Footnote Cancer is a disease characterized by uncontrolled cell growth due to mutations.
63
Can cancer genes be inherited?
Yes ## Footnote Some mutations that lead to cancer can be passed down from parents to offspring.
64
What is gene expression?
The use of a gene whose product is necessary for a specific moment.
65
How many genes does each cell have?
At least 20,000 genes.
66
Do all cells make the same proteins?
No, different cells make different proteins.
67
What determines the different structures and functions of cells?
Different proteins made by expressing different genes.
68
What is the process of using a gene to make a protein called?
Gene expression.
69
Why is gene expression regulated?
To ensure correct proteins are made when and where needed.
70
At what stages can gene expression be regulated?
Regulation can occur at any point from transcription to post-translational modifications.
71
List the stages where gene expression is regulated.
* Chemical and structural modification of DNA or chromatin * Transcription * Translation * Post-transcriptional modification * RNA transposon * mRNA degradation * Post-translational modifications
72
True or False: All cells in the body have the same genes.
True.
73
Fill in the blank: The process of modifying protein after translation is called _______.
[Post-translational modifications]
74
What controls transcription at the level of gene regulation?
Regulatory proteins binding to the DNA
75
What is a regulatory protein also known as?
Transcription factor
76
What do regulatory proteins bind to in order to switch genes on or off?
Cis-regulatory element
77
What are the two types of regulatory proteins?
Activators and repressors
78
Fill in the blank: Transcription factors alter the specificity of RNA polymerase for a _______.
[promoter or set of promoters]
79
What do activator proteins do in gene regulation?
Enhance the interaction between RNA polymerase and a particular promoter
80
What is the role of repressor proteins?
Bind to non-coding sequences on the DNA that impede RNA polymerase's progress
81
What are basal factors?
Transcription factors that help position RNA polymerase at the start of a gene
82
What are enhancers in the context of gene regulation?
Sites on the DNA bound by activators to loop the DNA, bringing a transcription factor to the initiation complex
83
What is an initiation complex composed of?
RNA polymerase and numerous transcription factors
84
True or False: As organisms grow more sophisticated, gene regulation becomes simpler.
False
85
What can a mutation in a cis-regulatory region affect?
The proper expression of a gene
86
What can happen if a gene is kept permanently off due to a mutation?
No protein can be made
87
What can happen if a gene is kept permanently on due to a mutation?
The corresponding protein is constantly made
88
What can detrimental effects on the cell result from?
Permanent off or permanent on states of gene expression
89
How is transcription regulated differently in prokaryotes compared to eukaryotes?
Prokaryotic regulation is simpler than eukaryotic regulation.
90
What is an operon?
An operon is a region of DNA that consists of one or more genes that encode proteins needed for a specific function, along with a promoter and an operator.
91
What is the function of the operator in an operon?
The operator is a region where regulatory proteins bind to help regulate transcription of the operon genes.
92
What components make up the lac operon?
The lac operon consists of a promoter, an operator, and three genes that encode enzymes needed to digest lactose.
93
What happens when lactose is absent in the lac operon?
A repressor protein binds to the operator, blocking RNA polymerase from binding to the promoter, so the lac genes are not expressed.
94
What occurs when lactose is present in the lac operon?
The repressor protein does not bind to the operator, allowing RNA polymerase to bind to the promoter and begin transcription, resulting in the expression of lac genes.
95
Fill in the blank: The _______ operon is a well-known example of operon regulation in E. coli.
lac
96
True or False: The lac operon is regulated by the presence of lactose in the environment.
True
97
What is one of the most complicated parts of gene regulation in eukaryotic cells?
The start of transcription
98
What role do enhancers play in eukaryotic gene regulation?
They are distant regions of DNA that can loop back to interact with a gene's promoter.
99
What is the TATA box?
A regulatory element that is part of the promoter of most eukaryotic genes.
100
What is the core sequence of the TATA box?
TATAAA
101
What must occur for RNA polymerase to recognize and bind to the promoter?
All of the appropriate proteins must be bound to the TATA box.
102
What is the significance of regulatory proteins during the development of an organism?
They must turn on certain genes in particular cells at the right time for normal development.
103
What are homeobox genes?
Genes that code for regulatory proteins that switch on major developmental genes.
104
What are hox genes?
A type of homeobox gene that ensures body parts develop in the correct place.
105
True or False: The patterns of regulatory elements in different cell types are the same.
False
106
Fill in the blank: A mutation in a _______ gene can affect an insect's development.
hox
107
What happens when RNA polymerase binds to the promoter?
Transcription begins.
108
What are the two types of regulatory genes that mutations causing cancer generally occur in?
Tumor-suppressor genes and proto-oncogenes
109
What do tumor-suppressor genes and proto-oncogenes produce?
Regulatory proteins that control the cell cycle
110
What happens when tumor-suppressor genes or proto-oncogenes mutate?
Cells with mutations divide rapidly and without limits
111
What potential result can occur from cells dividing rapidly and without limits?
A tumor and cancer
112
Fill in the blank: Mutations that cause cancer generally occur in _______.
tumor-suppressor genes and proto-oncogenes
113
True or False: Mutations in regulatory genes can lead to uncontrolled cell division.
True
114
What are the two types of regulatory genes that mutations causing cancer generally occur in?
Tumor-suppressor genes and proto-oncogenes
115
What do tumor-suppressor genes and proto-oncogenes produce?
Regulatory proteins that control the cell cycle
116
What happens when tumor-suppressor genes or proto-oncogenes mutate?
Cells with mutations divide rapidly and without limits
117
What potential result can occur from cells dividing rapidly and without limits?
A tumor and cancer
118
Fill in the blank: Mutations that cause cancer generally occur in _______.
tumor-suppressor genes and proto-oncogenes
119
True or False: Mutations in regulatory genes can lead to uncontrolled cell division.
True

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