B4- Genetic information, variation and relationships between organisms

Question 1

Length of DNA in eukaryotes?

Answer 1

Longer

Question 2

Length of DNA in prokaryotes?

Answer 2

Shorter

Question 3

Shape of DNA in eukaryotes?

Answer 3

Linear

Question 4

Shape of DNA in prokaryotes?

Answer 4

Circular

Question 5

Proteins associated with DNA in eukaryotes?

Answer 5

Histones

Question 6

Proteins associated with DNA in prokaryotes?

Answer 6

None

Question 7

Are introns present in eukaryotes or prokaryotes?

Answer 7

Present in both

Question 8

What is an intron?

Answer 8

A non-coding piece of DNA

Question 9

What four things is a genetic code said to be?

Answer 9

• A triplet code
• Degenerate
• Non-overlapping
• Universal

Question 10

What is the triplet code?

Answer 10

Each amino acid is coded by three bases

Question 11

How many different combinations are there in the triplet code?

Answer 11

64

Question 12

How many types of amino acid are there?

Answer 12

20

Question 13

What does the amount of possible combinations of the triplet code compare with the amount of different types of amino acid tell us?

Answer 13

That more than one code can code for an amino acid.

Question 14

Name the process by which mRNA is formed in the nucleus.

Answer 14

Transcription

Question 15

What does degenerate mean in terms of the genetic code?

Answer 15

Some of the 20 amino acids can be specified by more than one codon.

Question 16

What does non-overlapping mean in terms of the genetic code?

Answer 16

The triplet code is read once in its correct sequence of three

Question 17

What does universal mean in terms of the genetic code?

Answer 17

It is the same in all living organisms

Question 18

What are the three types of gene mutation?

Answer 18

• Base Insertion
• Base deletion
• Base substitution

Question 19

Why don’t all base substitutions cause a change in the sequence of encoded amino acids?

Answer 19

Code is degenerate (some of the 20 amino acids can be specified by more than one codon)

Question 20

What is a mutagenic agent?

Answer 20

A chemical, physical, or biological agent that increases risk of mutation in the cell’s DNA (e.g radiation)

Question 21

What are homologous pairs?

Answer 21

Two chromosomes which carry the same genes.

Question 22

What is a haploid?

Answer 22

Half the number of genetic info

Question 23

What is a diploid?

Answer 23

Normal amount of genetic info

Question 24

What is independent segregation?

Answer 24

A form of chromosome mutation where the chromosomes in a homologous pair are separated in Meiosis 1 in a random formation to produce two genetically different daughter cells.

Question 25

What two ways can genetic variation occur during mitosis?

Answer 25

Crossing over & independent segregation

Question 26

What is Crossing over?

Answer 26

When alleles are exchanged/ 'cross over'

Question 27

What is non-disjunction?

Answer 27

The failure of homologous chromosomes (meiosis I) or sister chromatids (meiosis II) to separate properly during meiosis

Question 28

What is genetic diversity?

Answer 28

The number of different alleles of genes in a population

Question 29

What is allele frequency?

Answer 29

How often different alleles occur in the gene pool of a population

Question 30

Four sources of genomic variation/changes in allele frequency

Answer 30

-Genetic drift -The founder effect -The bottleneck effect -Natural selection

Question 31

What is genetic drift?

Answer 31

When a population is very small, chance can affect which alleles get passed onto the next generation

Question 32

What is the Founder effect?

Answer 32

When a small number of individuals from a larger population start a new population

Question 33

What is the Bottleneck effect?

Answer 33

When a previously large population suffers a dramatic fall in numbers (e.g a natural disaster)

Question 34

What is Natural selection?

Answer 34

Selection pressures produce a gradual change in allele frequencies over several generations

Question 35

What are the two types of selection?

Answer 35

-Stabilising selection -Directional Selection

Question 36

What is stabilising selection?

Answer 36

Those at the extremes of the phenotypic range are selected against.

Question 37

What is directional selection?

Answer 37

Individuals with alleles for a single extreme phenotype are selected for.

Question 38

What is classification?

Answer 38

organising living things into groups based on accepted principles.

Question 39

Taxonomy order

Answer 39

Kingdom Phylum Class order Family Genus Species

Question 40

What is a euglena?

Answer 40

A unicellular organism

Question 41

What is a binomial name?

Answer 41

Genus nama, species name

Question 42

What is courtship behaviour?

Answer 42

Physical resemblance and behaviour is similar in the same species

Question 43

What are the purposes of courtship behaviour?

Answer 43

- Identify a mate - Become able to breed - Synchonise mating - Form a pair bond - Recognition of individuals of same experience

Question 44

What is taxonomy?

Answer 44

The study of the principles behind classification

Question 45

Two types of classification

Answer 45

-Artificial classification (visible differences) -Phylogenic classification (evolutionary relationships)

Question 46

Three ways to clarify evolutionary relationships

Answer 46

- Genome and DNA sequencing - Amino acid sequence - Immunological comparison