Unit 1: Human Cells - Key Area 3 - Gene expression Flashcards

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1
Q

What is RNA?

A

A nucleic acid with a similar structure to DNA.

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2
Q

What are the three types of RNA?

A
  • Messenger RNA (mRNA)
  • Transfer RNA (tRNA)
  • Ribosomal RNA (rRNA)
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3
Q

What is the function of transfer RNA?

A

Picks up a SPECIFIC amino acid from the cytoplasm and brings it to the ribosome.

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4
Q

What is the function of messenger RNA?

A

Carries the genetic code from the nucleus to the ribosome.

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5
Q

What is the function of ribosomal RNA?

A

Along with protein, it gives structure to the ribosome.

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6
Q

Where is mRNA made?

A

In the nucleus.

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7
Q

When is mRNA’s function used?

A

The first stage of protein synthesis.

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8
Q

When is tRNA’s function used?

A

The second stage of protein synthesis.

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9
Q

What does RNA consist of?

A

Nucleotides.

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10
Q

In RNA what are the four types of bases?

A

Adenine, cytosine, guanine, and uracil replaces thymine.

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11
Q

What is the complementary base pair for adenine in RNA?

A

Uracil.

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12
Q

How are proteins made?

A

Proteins are made by joining together amino acids in a specific sequence.

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13
Q

What does the protein produced by protein synthesis rely on?

A

The order of amino acids which is dictated by the order/sequence of the bases on the DNA.

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14
Q

What are the two main stages of protein synthesis?

A

Transcription and Translation.

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15
Q

What are the stages of transcription?

A
  • The section of DNA which codes for the desired protein unwinds and unzips. This is carried out by an enzyme called RNA polymerase.
  • Free RNA nucleotides enter the nucleus and RNA POLYMERASE joins them with their complementary DNA base starting at the 3’ end.
  • Only one strand is copied.
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16
Q

What is the strand of mRNA produced by transcription called?

A

The Primary Transcript.

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17
Q

Why is only one gene transcribed to form mRNA?

A

So the Primary Transcript only codes for one protein.

18
Q

What does the primary transcript contain?

A

It contains regions that code for the production of the protein called Exons and regions which are non-codingwhich are calledIntrons.

19
Q

What are the introns of the primary transcript?

A

Introns are non-coding regions that have to be removed.

20
Q

What are the exons of the primary transcript?

A

Exons are coding regions and are joined together to form the mature transcript.

21
Q

What is DNA splicing?

A

DNA splicing is where introns are removed and the exons are joined together to form a mature transcript of mRNA.

22
Q

What happens once the mature transcript of mRNA is produced?

A

The mature mRNA leaves the nucleus and enters the cytoplasm.

23
Q

Where is tRNA found?

A

In a cells cytoplasm

24
Q

What is the function of tRNA?

A

To pick up a specific amino acid and bring them to the ribosome.

25
Q

What is the structure of tRNA

A

The tRNA is a strand of RNA which is folded due to the hydrogen bonds. The folding forms an anticodon and an amino acid binding site. The amino acid bonding site can only pick up one specific amino acid.

26
Q

What is translation?

A

Translation is the synthesis of a protein in the form of a polypeptide chain of amino acids.

27
Q

What is translation under the control of?

A

Translation is under the control of and dictated by mRNA as it carries the genetic code from the DNA.

28
Q

What does each codon contain?

A

Each codon contains the code for one amino acid.

29
Q

What are amino acids often referred to?

A

The building blocks of a protein.

30
Q

Where does translation occur?

A

Translation occurs on the ribosome.

31
Q

What is the start codon for translation?

A

AUG is the start codon.

32
Q

What does the start codon indicate?

A

The start codon indicates to the tRNA where to add the first amino acid.

33
Q

What happens to the tRNA after the polypeptide is formed?

A

It leaves the ribosome once the polypeptide has been formed.

34
Q

What are amino acids linked by and what does this form?

A

Amino acids are linked by peptide bonds to form polypeptides.

35
Q

What does the polypeptide fold to form and how is this held together?

A

Polypeptide chains fold to form the three-dimensional shape of a protein, held together by hydrogen bonds and other interactions between individual amino acids.

36
Q

What do proteins have a large variety of and what does this do?

A

Proteins have a large variety of shapes which determines their functions.

37
Q

What is the phenotype determined by?

A

Phenotype is determined by the proteins produced as the result of gene expression.

38
Q

How can different proteins be expressed form one gene?

A

Different proteins can be expressed from one gene, as a result of alternative RNA splicing.

39
Q

What are the bonds between the amino acids in a polypeptide chain?

A

Hydrogen bonds

40
Q

What is gene expression?

A

The switching on or off of a gene to make a specific protein.