4:2 Gene Expression Flashcards

1
Q

What is a gene?

A

A unit of inheritance.

A specific sequence of nucleotides on DNA containing information for the formation of a functional product.

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2
Q

What is an allele?

A

An alternative sequence of DNA to a gene which may result in formation of a functional/non-functional product

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3
Q

What is transcription?

A

The process that makes an RNA copy of DNA

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4
Q

What is translation?

A

The process that uses information in the RNA to synthesize protiens

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5
Q

What is an example of how the nature of the genetic code is degenerate but specific?

A

Every codon codes for only one amino acid but some amino acids are specified by more than one codon

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6
Q

Example of how is genetic code triplet in nature?

A

UUU
UUA
UUC
Etc

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7
Q

State the three properties of the genetic code

A
  1. Triplet in nature
  2. Degenerate but specific
  3. Almost universal
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8
Q

Give an example of how the genetic code is nearly universal?

A

In mitochondria, chloroplasts and some some organisms, there are slight difference in stop codons

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9
Q

What is the relationship between the non template strand and the template strand?

A

They are complementary.

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10
Q

What is the relationship between the non-template strand and the mRNA strand?

A

They are similar

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11
Q

What is the relationship between the template strand and mRNA?

A

They are complementary (RNA pairing)

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12
Q

Describe transcription

A
  1. The DNA carrying the gene unwinds and unzips and the two DNA strands are separated.
  2. One of the DNA strands called the template strand is used to make the mRNA
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13
Q

What happens to the mRNA after transcription?

A

It leaves the nucleus through the nuclear pore.
It then attaches to a ribosome.
It then moves on to translation.

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14
Q

What is mRNA translation?

A
  1. The ribosome translates the message in mRNA into a sequence of amino acids joined together to form a polypeptide

As the ribosome moves along the mRNA, The polypeptide produced gets longer as more amino acids are joined together by peptide bonds.
At the end of the mRNA strand in the ribosomes detaches from the mRNA and the polypeptide is released.

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15
Q

What are the four types of genetic code Mutations?

A

Silent
Missense
Nonsense
Frameshift

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16
Q

What causes the silent mutation of a gene?

A

A change in the nucleotide sequence that does not change the amino acid specified by a codon

17
Q

What is the effect of a silent mutation?

A

There is no change to the protein structure.

18
Q

What is the cause of missense mutation in genes

A

It is a change in nucleotide sequence that changes the amino acid specified by codon

19
Q

What is the effect of the missense mutation?

A

This results in a change in primary structure of protein which may be beneficial, neutral or deleterious

20
Q

What causes the nonsense mutation in genes?

A

A change in the nucleotide sequence that results in a early stop codon

21
Q

What is the effect of a nonsense mutation?

A

A shortened polypeptide, usually deleterious.

22
Q

What is the cause of the frameshift mutation in genes?

A

A change in the reading frame of the nucleotide sequence. Caused by an addition or deletion of a nucleotide.

23
Q

What is the effect of frameshift mutation?

A

This causes a drastic change in the sequence of amino acids after the point of mutation. This results in change in primary structure of protein and is almost always deleterious

24
Q

What are chromosomes mutations due to?

A
  1. Deletions
  2. Duplications
  3. Inversions
  4. Translocations
25
Q

What are inversions in chromosomes

A

A region of a chromosome breaks, reverses, and rejoins the same chromosome

26
Q

What are translocations in chromosomes?

A

It is the breaking of a region of a chromosome and joining another chromosome

27
Q

What are the effects of changes in a chromosome number?

A

It can result in non disjunction events during mitosis or meiosis. This is when homologous or sister chromatids fail to separate properly. This condition is called a aneuploidy