Genetics

Question 1

What is the phenotype?

Answer 1

Physical manifestation of genes.

Question 2

What is the genotype?

Answer 2

Full genetics of genes.

Question 3

What is DNA composed from?

Answer 3

Nucleotide monomers.

Question 4

What is a nucleotide composed from?

Answer 4

Nitrogenous base
Phosphate group
Sugar

Question 5

What does the double helix shape result in?

Answer 5

Major and minor grooves.

Question 6

Why are major grooves in the double helix important?

Answer 6

Binding sites for proteins.

Question 7

What are the complementary base pairs of DNA?

Answer 7

Cytosine and Guanine

Thymine and adenine

Question 8

What does uracil pair with in mRNA?

Answer 8

Adenine.

Question 9

What is the sugar-phosphate backbone of DNA composed of?

Answer 9

Deoxyribose sugar and phosphate group link at 3’-5’ ends.

Question 10

What does the nucleus contain?

Answer 10

Genetic information.

Question 11

What occurs in the nucleus?

Answer 11

DNA replication

First steps of transcription

Question 12

What is chromatin?

Answer 12

Chromatin is the name given to the mixture of DNA, proteins and RNA that package DNA within the nucleus.

Question 13

What are heterochromatin and and euchromatin?

Answer 13

The condensed and extended forms of chromatin in the nucleus.

Question 14

What processes require the 2 strands of DNA to separate temporarily to allow enzymes access to the DNA template?

Answer 14

DNA replication

Transcription

Question 15

What poses a barrier to enzymes during DNA replication/transcription?

Answer 15

Nucleosomes and folding of chromatin barriers.

Question 16

How can chromatin be made more accessible?

Answer 16

Histones are enzymatically modified

Histones are displaced by chromatin remodelling complexes

Question 17

What is DNA replication semi-conservative?

Answer 17

One half of DNA is new and one is old.

Question 18

In what direction is DNA replicated?

Answer 18

5’ to 3’.

Question 19

What enzyme adds nucleotides in DNA replication?

Answer 19

DNA polymerase.

Question 20

Why is DNA replicated in a 5’-3’ direction?

Answer 20

DNA polymerase can only add it in that direction.

Question 21

When are chromosomes most compacted and visible?

Answer 21

Metaphase.

Question 22

What are coding regions called?

Answer 22

Exons.

Question 23

What are non-coding regions called?

Answer 23

Introns.

Question 24

How does genetic code allow DNA sequences to code for proteins?

Answer 24

Sets of 3 form codons which code for amino acids?

Question 25

What codes for the amino acid?

Answer 25

Codon.

Question 26

What is degeneracy/redundancy of genetic code?

Answer 26

The fact that most proteins are coded for by more than one codon.

Question 27

What is the role of RNA?

Answer 27

To transport DNA from nucleus to cytoplasm for ribosome travel for protein synthesis.

Question 28

What is mRNA transcribed from?

Answer 28

DNA.

Question 29

What happens during alternative DNA splicing?

Answer 29

Exon coding regions are reconnected in a different way to increase variation and allow generation of more protein functions.

Question 30

What is the role of tRNA?

Answer 30

To translate the mRNA sequence into an amino acid sequence.

Question 31

What does tRNA act as?

Answer 31

Adaptor molecule.

Question 32

What is rRNA?

Answer 32

Component of ribosomes

Question 33

Where does rRNA combine with proteins to form a ribosome?

Answer 33

Cytoplasm.

Question 34

What is it called when several ribosomes can translate DNA at one time?

Answer 34

Polysome.

Question 35

What are telomeres?

Answer 35

5'-3' repeats.

Question 36

What are the stages of mitosis?

Answer 36

Prophase Metaphase Anaphase Telophase

Question 37

What happens in prophase?

Answer 37

Chromosomes condense.

Question 38

What happens in metaphase?

Answer 38

Chromosomes line up at the equator of the cell.

Question 39

What happens in anaphase?

Answer 39

Spindle fibres form, move to opposite ends of the cell.

Question 40

What happens in telophase?

Answer 40

New nuclear membranes form.

Question 41

What is cytokinesis?

Answer 41

Division to form 2 daughter cells.

Question 42

At what stage are chromosomes most condensed?

Answer 42

Metaphase.

Question 43

What does mitosis produce?

Answer 43

Diploid cells with 46 chromosomes.

Question 44

What are centromeres?

Answer 44

Constricted region joining sister chromatids.

Question 45

When does DNA replication occur?

Answer 45

Interphase- S phase.

Question 46

What enzymes does DNA replication require?

Answer 46

Helicase DNA polymerase Ligase Primase

Question 47

Where does DNA replication occur?

Answer 47

Nucleus.

Question 48

What does helicase do?

Answer 48

Unwinds DNA from origin point by breaking hydrogen bonds.

Question 49

What does primase do?

Answer 49

Makes RNA primers on both strands which shows DNA polymerase where to start.

Question 50

What direction does DNA polymerase add in?

Answer 50

5'-3'.

Question 51

Why does DNA polymerase add in the 5'-3' direction?

Answer 51

Moves along old template in 3'-5' direction.

Question 52

What is the lagging strand?

Answer 52

The new strand.

Question 53

What are primer fragments called and joined by?

Answer 53

Okazaki fragments sealed by ligase.

Question 54

Why is DNA replication semi-conservative?

Answer 54

Because 2 copies of each contains 2 strands and one is old with the other being new.

Question 55

What structure does heterochromatin have?

Answer 55

Condensed structure, silenced genes.

Question 56

What structure does euchromatin have?

Answer 56

Open structure, active genes.

Question 57

Are genes silenced or active in heterochromatin?

Answer 57

Silenced.

Question 58

Are genes silenced or active in euchromatin?

Answer 58

Active.

Question 59

What is DNA packaged with to form chromatin?

Answer 59

Histone proteins.

Question 60

What charge do histone proteins have?

Answer 60

Positive.

Question 61

What are DNA/chromatin/histone complexes packaged into?

Answer 61

Nucleosomes.

Question 62

What is the karyotype?

Answer 62

Chromosome structure arrangement.

Question 63

What happens in transcription?

Answer 63

RNA polymerase binds to DNA promoter region and creates template strand- it uses this to synthesis mRNA from 5'-3' end through elongation.

Question 64

What is elongation?

Answer 64

Synthesis of mRNA from 5'-3' end.

Question 65

What direction does RNA polymerase synthesis mRNA?

Answer 65

5'-3' end.

Question 66

What are the differences between RNA and DNA?

Answer 66

RNA is single stranded Ribose sugar instead of deoxyribose Uracil base instead of thymine

Question 67

What happens when mRNA is produced?

Answer 67

Moves to ribosome for translation.

Question 68

What does mRNA act as?

Answer 68

Specific code for proteins.

Question 69

How does mRNA act as a code?

Answer 69

3-base codons pair with anti-codons on tRNA which are linked to amino acids.

Question 70

What does tRNA do?

Answer 70

Links mRNA to amino acids.

Question 71

What is rRNA?

Answer 71

Ribosomal RNA.

Question 72

What are FISH probes?

Answer 72

Fluorescent in situ hybridisation probes.

Question 73

What are the types of FISH probe?

Answer 73

Centromeric (number) Telomeric (kids with mental retardation) Whole chromosome

Question 74

What are centromeric FISH probes used for?

Answer 74

Determining chromosome number.

Question 75

What are telomeric FISH probes used for?

Answer 75

Subtelomeric arrangement- kids with unexplained mental retardation.

Question 76

What are whole chromosome FISH probes used for?

Answer 76

Translocation and rearrangement.

Question 77

What is meiosis?

Answer 77

Cell division in germline cells.

Question 78

What does meiosis produce?

Answer 78

Haploid cells from diploid cells.

Question 79

How is genetic diversity promoted within meiosis?

Answer 79

Recombination.

Question 80

When does recombination occur in meiosis?

Answer 80

Prophase I

Question 81

What is oogenesis?

Answer 81

Process of egg formation.

Question 82

What is spermatogenesis?

Answer 82

Process of sperm formation.

Question 83

Why is there more chance of mutation in sperm?

Answer 83

Increase division.

Question 84

Where do mitochondrial genes come from?

Answer 84

Maternal origin.

Question 85

What is X-inactivation?

Answer 85

Due to double XX genotype in mother, one X chromosome may be deactivated and just the other passed on.