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Flashcards in Storing and Using Genetic Information Deck (68)
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1
Q

What is a phenotype

A

A outward, physical manifestation of organism

2
Q

What is a genotype

A

The full hereditary information of organism (even if not expressed)

3
Q

Why are proteins all functionally different

A

Due to their structure

4
Q

What is protein structure dependent on

A

The primary structure and therefore the specific sequence of amino acids

5
Q

What is the molecular structure of DNA

A

It is a chain of nucleotide monomers

6
Q

What does each nucleotide contain

A

Sugar
Base
Phosphate group

7
Q

What is the sugar on DNA called

A

2’ - deoxyribose

8
Q

What shape do DNA molecules form

A

Double helix

9
Q

What is the backbone of DNA

A

Sugar phosphate

10
Q

How many bases are there for every full turn of the helix in DNA

A

10

11
Q

Do the polynucleotide chains run parallel or anti-parallel to each other

A

Anti-parallel

One runs 5’ to 3’ while the other runs 3’ to 5’

12
Q

How does the polynucleotide chains running anti-parallel to each other affect the double helix

A

It allows it to remain stable

13
Q

What does the way the double helix is wound result in

A

Major groove

Minor groove

14
Q

In which groove are many binding sites found

A

Major

15
Q

Why are the grooves formed important in DNA

A

For the interaction of proteins with the DNA molecule

16
Q

Is the double helix, right or left handed

A

Right handed

17
Q

What are the bases in DNA

A

Adenine
Cytosine
Guanine
Thymine

18
Q

How to the bases pair in DNA

A

A-T

C-G

19
Q

Which base is switched in RNA

A

Thymine becomes Uracil

20
Q

How many bonds are found between A-T

A

2 hydrogen bonds

21
Q

How many bonds are found between C-G

A

3 hydrogen bonds

22
Q

Describe the nucleus

A

The largest organelle in the cell
Contains most of the cell’s genetic material (DNA)
Replication of DNA and the first steps in decoding it for protein production take place in the nucleus

23
Q

How big is the nucleus

A

5-10 μm in diameter

24
Q

When are chromosomes visible in a cell

A

Only when the cell is dividing

25
Q

What is DNA packaged into in the nucleus

A

Thread-like structures called chromosomes

26
Q

What are chromosomes

A

A single piece of DNA containing many genes, regulatory elements and other nucleotide sequences

27
Q

How many chromosomes do humans have

A

46

28
Q

What is chromatin

A

The mixture of DNA, proteins and RNA that package DNA within the nucleus

29
Q

Which two forms of chromatin can be found

A

Heterochromatin (condensed)

Euchromatin (extended)

30
Q

What do transcription and replication require

A

The two strands of DNA to separate temporarily to allow enzymes access to the DNA template

31
Q

What are barriers to enzymes in transcription and replication

A

Nucleosomes and folding of chromatin

32
Q

Name two major reversible mechanisms by which chromatin is made more accessible

A

Histones can be enzymatically modified

Histones can be displaced by chromatin remodeling complexes

33
Q

What does it mean when it is said that DNA replication is semi-conservative

A

One-half of each new molecule of DNA is old; one-half new

34
Q

What must be broken to split the double helix

A

Hydrogen bonds

35
Q

In what direction is DNA replicated

A

5’ to 3’

36
Q

Where can DNA polymerase add new nucleotides

A

Only to the 3’ end of the growing strand

37
Q

What are formed on the lagging strand

A

Okazaki fragments

38
Q

How are okazaki fragments joined to produce one continuous strand

A

By DNA ligase

39
Q

How is the 5’ end of the lagging strand replicated

A

A specialized enzyme, telomerase, replicates the 5’ ends of the lagging strand

40
Q

How many bases are exactly the same in all people

A

99.9%

41
Q

What are exons

A

Coding regions

42
Q

What are introns

A

Non-coding regions

43
Q

What happens to introns and exons in transcription

A

Introns - eliminated

Exons - spliced

44
Q

What does the genetic code describe

A

How base sequences are converted into amino acids

45
Q

What is a set of three bases called

A

Codon

46
Q

What does each codon specify

A

A particular amino acid

47
Q

How many codons can be formed from 4 bases

A

4^4 = 64 codons

48
Q

How many amino acids have been found in proteins

A

20

49
Q

Which amino acids are only coded for by one codon

A

Methionine

Tryptophan

50
Q

What is methionine also termed

A

Initiation codon as this is the signal for protein synthesis to begin

51
Q

What is degeneracy

A

The number of codons is greater than the number of amino acids

52
Q

What can single point mutations cause

A

Dysfunctional proteins

53
Q

Give an example of a single point mutation producing a dysfunctional protein

A

Mutated haemoglobin gene causes Sickle Cell Anaemia
In the mutant hemoglobin a hydrophilic glutamate (Glu) is substituted by the hydrophobic valine (Val), (GAA or GAG becomes GUA or GUG)

54
Q

What is the major role of RNA

A

To participate in protein synthesis

55
Q

What types of RNA are there

A
Messenger RNA (mRNA)
Transfer RNA (tRNA)
Ribosomal RNA (rRNA)
56
Q

What is mRNA

A

It is transcribed from DNA and carries information for protein synthesis

57
Q

What is alternative splicing

A

A process by which the exons of the RNA produced by transcription of a gene (a primary gene transcript or pre-mRNA) are reconnected in multiple ways during RNA splicing

58
Q

What does alternative splicing result in

A

The resulting different mRNAs may be translated into different protein isoforms; thus, a single gene may code for multiple proteins

59
Q

What does alternative splicing increase

A

Diversity of proteins that can be encoded by the genome

60
Q

What does the initiation codon determine

A

The reading frame of the RNA sequence.

61
Q

What is a open reading frame

A

A set of codons runs continuously and is bounded by a start/initiation codon and a termination codon

62
Q

What does the open reading frame identify

A

DNA which encodes protein sequences in genome sequencing projects

63
Q

What occurs in the nucleus

A

Transcription (DNA to mRNA) and alternative splicing

64
Q

What occurs in the cytoplasm

A

Post translational modifications

tRNA, rRNA and protein present here

65
Q

What is the major role of tRNA

A

To translate mRNA sequence into amino acid sequence

Acts as an adapter molecule between the coded amino acid and the mRNA

66
Q

What is rRNA

A

A component of ribosomes

67
Q

Where are rRNA molecules produced

A

In the nucleus

Transported to cytoplasm, where they combine with proteins to form a ribosome

68
Q

What is a polysome

A

Several ribosomes can translating mRNA at one time