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Flashcards in B1 Genetics Deck (40)
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1
Q

What is a gene?

A

A distinct sequence of nucleotides forming part of chromosome.The order determines the order of monomers in a polypeptide/ nucleic acid molecule that the cell may synthesise

2
Q

What is the purpose of non-coding RNAs?

A

Controlling levels of genes that do code for proteins

3
Q

What is the process that converts DNA to pre-mRNA?

A

Transcription

4
Q

What is the process that converts pre-mRNA into mRNA?

A

Splicing

5
Q

What is the process that makes protein from mRNA?

A

Translation

6
Q

How is the location and time of gene transcription controlled?

A

Promoter and regulatory sequences

7
Q

What enzyme is responsible for the transcription of the gene?

A

RNA polymerase(DNA helicase helps!)

8
Q

What is the role of transcription factors?

A

They bind to the promoter and regulatory sequences and influence gene transcription

9
Q

Which strand is the template strand? Sense or antisense?

A

Antisense

10
Q

Which DNA strand corresponds with the amino acid selected?

A

Sense

11
Q

In addition to splicing, what modifications occurbefore translation?

A

CappingPolyadenylation

12
Q

What is capping?

A

Cap structure is added to the 5’ end of the mRNAs shortly after the beginning of transcription

13
Q

What is polyadenylation?

A

Poly-A polymerase adds 100 to 300 Adenine residues to form a poly-A tail on the 3’ end.

14
Q

How are the levels of mature mRNA regulated after transcription?

A

microRNAs destabilise them and inhibit initiation of their translation

15
Q

What is the process that microRNAs are responsible for?

A

RNA-induced silencing

16
Q

The genetic code is degenerate, but unambiguous. What does this mean?

A

An amino acid can have more than one codon, but no codon codes for two different amino acids.

17
Q

What is the start codon/ initiator and what does it code for?

A

AUG - Methionine

18
Q

What is the stop codon known as?

A

Open reading frame (ORF)

19
Q

What is the small ribosomal sub-unit responsible for?

A

Binding mRNA and tRNA

20
Q

What is the large ribosomal sub-unit responsible for?

A

Catalyzes addition of amino acids to extending peptide chain.

21
Q

What end of the mRNA does the small sub-unit scan from?

A

5’ end

22
Q

What end is the initiator at on the mRNA?

A

5’ end

23
Q

In termination, what recognises the stop codon?

A

A releasing factor

24
Q

What are releasing factors responsible for?

A

Causing the ribosome complex to fall apart; ending translation

25
Q

True or false? Many antibiotics are inhibitors of protein synthesis in bacteria?

A

True

26
Q

What is the key to good antibiotics?

A

Making use of the structural and functional differences between prokaryotic cells (them) and eukaryotic cells (us)

27
Q

Following translation,what modifications can occur for proteins?

A

GlycosylationPhosphorylationUbiquitination for misfolded proteins

28
Q

How is the function and localisation of a protein determined?

A

Structure and post-translational modification

29
Q

What is ubiquitin?

A

A small chemical moiety

30
Q

What happens in ubiquitination and why?

A

Proteins are degraded because they were misfolded.

31
Q

Many proteins in the nucleus contain what kind of signal?

A

Nuclear localisation signal

32
Q

In cases where there are not specific signals in the peptide sequence, how are proteins transported to the nucleus?

A

They are phosphorylated

33
Q

What signal do proteins secreted from the cell/ inserted into the plasma membrane have at their amino terminus?

A

ER/ endoplasmic reticulum signal sequence / peptide

34
Q

What is the location of protein modification?

A

Golgi Apparatus

35
Q

What is the contents of a nucleus?

A

Chromatin
Nuclear Envelope
Nuclear Pore
Nucleolus

36
Q

What is the majority of a nucleolus made from?

A

RNA

37
Q

What is a nucleoplasm?

A

A nuclear substance containing chromatin and RNA.

38
Q

What is genetic polymorphism?

A

2 or more variants of an allele

39
Q

True or false? Most genes are polymorphic?

A

True

40
Q

List examples of point mutations in base sequences

A

Insertion

Deletion