DNA Test Part Three: Gene Mutation And Regulation Flashcards Preview

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Flashcards in DNA Test Part Three: Gene Mutation And Regulation Deck (33):
1

Gene Mutation

Heritable changes in genetic information

2

Substitution

The change of one base to another in a DNA sequence

3

Point mutation

A change in one or a few nucleotides that occur at a single point in the DNA sequence

4

Frameshift mutation

A kind of mutation that can change every amino acid that follows the point of mutation

5

Insertion

The addition of a base to the DNA sequence

6

Translocation

Part of one chromosome breaks off and attaches to another

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Inversion

A chromosomal mutation that reverses the direction of parts of a chromosome

8

Duplication

A mutation that produces an extra copy of all or part of a chromosome

9

Difference between deletion as a gene mutation or chromosomal mutation

As a gene mutation one base is removed from the DNA sequence while in a chromosomal mutation the deletion would involve the loss of one or more chromosomes

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Effect of Substitution

Only affects the amino acid if anything

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Effect of Insertion

Affects every amino acid that comes after the mutation

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Effect of deletion

Affects every amino acid that comes after the mutation

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Mutagen

An agent such as radiation or a chemical substance that causes genetic mutation

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Gene regulation

Gene regulation is the process of controlling which genes in a cell's DNA are expressed (used to make a functional product such as a protein)

15

P How do prokaryotes conserve energy

Prokaryotes regulate their activities producing only those genes necessary for the cell to function

16

P How do DNA binding proteins in prokaryotes regulate genes

They control transcription. Some of these regulatory proteins help switch genes on,
while others turn genes off

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P What is an operon

It is a group of genes that are regulated together

18

P What is the lac operon is E. coli

three genes

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P What is the function of the genes in the lac operon of E. coli

They allow E. coli to use lactose for food when it is present.

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P What turns the lac operon off

A repressor protein turns the operon off.

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P How does a repressor protein turn off the lac operon

It binds to the operating region, blocking RNA polymerase from transcribing the lac
genes

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P How does lactose turn on the lac operon

It binds to the operating region, blocking RNA polymerase from transcribing the lac
genes

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Repressor protein

Binds to the operator, preventing transcription of the lac genes

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Operator

Binding site for the repressor protein

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RNA polymerase

When the repressor is not present this enzyme carries out the transcription of lac genes

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Lactose

Causes the repressor to drop off the operator so transcription of the lac genes can begin

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Lac genes

The lac operon (lactose operon) is an operon required for the transport and metabolism of lactose in Escherichia coli and many other enteric bacteria

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E Difference between gene regulation in prokaryotes and eukaryotes

a. Most eukaryotic genes are controlled individually.
b. Eukaryotic cells have more complex regulatory sequences than those of the lac
repressor system.

29

E TATA box

It is a short region of DNA that contains a sequence of T and A base pairs. The protein
that binds to this site helps position RNA polymerase.

30

E Transcription factors

They are DNA-binding proteins that bind to DNA sequences in the regulatory regions
of genes and help control gene expression.

31

How gene regulation makes cell specialization possible

It allows particular genes to be expressed in some kinds of cells but not others.

32

E. coli with a limited nutrient supply response

The lac operon is switched on when lactose is the only food source

33

Tadpole with a lack of water response

The tadpole may speed up it's metamorphosis