Genetic information, variation and relationships between organisms

Question 1

Definition of a gene?

Answer 1

A gene is a base sequence of DNA that codes for
- the amino acid sequence of a polypeptide
-a functional RNA (including ribosomal RNA and tRNAs)

Question 2

What is the locus?

Answer 2

The fixed position a gene occupies on a DNA molecule

Question 3

What is a triplet?

Answer 3

A sequence of three DNA bases coding for a specific amino acid.

Question 4

The genetic code

Question 5

Degenerate

Answer 5

More than one triplet can be coded for one amino acid

Question 6

Universal

Answer 6

Triplet code is the same code for all living organisms in one amino acid

Question 7

Non- overlapping

Answer 7

Each base is only part of one triplet codon

Question 8

What are introns?

Answer 8

Non coding regions of a gene

Question 9

What are exons?

Answer 9

Coding regions of a gene

Question 10

DNA in prokaryotes

Answer 10

Short, circular and not associated with proteins.

Question 11

DNA in eukaryotes

Answer 11

Long, linear and associated with proteins called histones. Together a DNA molecule and its associated proteins form a chromosome.

Question 12

DNA of mitochondria and chloroplasts

Answer 12

Short, circular and not associated with proteins.

Question 13

Genome

Answer 13

The complete set of genes in a cell

Question 14

Proteome

Answer 14

The full range of proteins that a cell is able to produce.

Question 15

Structure of chromosome

Answer 15

At start of cell division, they appear as two threads joint by a single thread (each thread known as chromatid). These are conjoined by a centromere.
DNA is held together by histones.

Question 16

Chromosomes in humans

Answer 16

46
23 pairs

Question 17

Chromosomes in gametes

Answer 17

23

Question 18

Homologous chromosomes

Answer 18

A pair of chromosomes, one maternal and one paternal which have the same gene loci

Question 19

What is an allele?

Answer 19

Different versions of the same gene

Question 20

Gene mutation

Answer 20

A change in the base/ nucleotide sequence of DNA resulting in the formation of a new allele

Question 21

Sources of DNA from organisms

Answer 21

Bone/ skin/ preserved remains

Question 22

Reasons for low levels of genetic diversity

Answer 22

• Inbreeding
• Population started with small number of individuals
• Population may have been very small

Question 23

RNA structure

Answer 23

A polymer forming a single strand.
- Pentose sugar ribose
- Nitrogen containing organic bases (adenine,guanine,cytosine, uracil)
- Phosphate group

Question 24

The two types of RNA in protein synthesis

Answer 24

messenger RNA (mRNA)
transfer RNA (tRNA)

Question 25

Structure of mRNA

Answer 25

Linear Exons Codon

Question 26

Structure of tRNA

Answer 26

Clover leaf shape Has specific amino acid binding site

Question 27

Function of transcription

Answer 27

The process of making mRNA from DNA

Question 28

Results of transcription - prokaryotic cell

Answer 28

Transcription results directly in the production of mRNA from DNA.

Question 29

Results of transcription - eukaryotic cell

Answer 29

Transcription results in the production of pre-mRNA which is then spliced to form mRNA.

Question 30

Function of translation

Answer 30

Translation as the production of polypeptides from the sequence of codons carried by mRNA.

Question 31

RNA polymerase role

Question 32

Ribosome role

Question 33

Role of tRNA

Question 34

Role of ATP

Question 35

What is the process of splicing?

Answer 35

Introns are removed from the pre-mRNA by the spliceosome and exons are spliced back together.

Question 36

What is a spliceosome?

Answer 36

Huge, multimegadalton ribonucleoprotein (RNP) complexes found in eukaryotic nuclei.

Question 37

Meiosis stages

Answer 37

Prophase, metaphase, anaphase, telophase - two stages process each stage occurring twice yet DNA only replicates once

Question 38

Crossing over

Answer 38

Process by which non sister chromatids exchange alleles and DNA

Question 39

Ways in which meiosis increases genetic variation?

Answer 39

- Exchange of genetic material between chromatids of maternal and paternal origin. (prophase) - Orientation of each paire of chromosomes one spindle is a random event. (metaphase) - Independant segregation

Question 40

What is meiosis?

Answer 40

Meiosis is a type of cell division which results in four genetically varied daughter cells

Question 41

Independant segregation

Answer 41

Separation of chromosomes, halving them resulting in four daughter cells with completely different combinations of maternal and paternal chromosomes. - Completely random event - Increases genetic variation

Question 42

Mutations

Question 43

Mutagenic agents

Question 44

Base deletion

Question 45

Base substitution

Question 46

Genetic diversity

Answer 46

The number of different alleles of genes in a population.

Question 47

Principles of natural selection

Answer 47

Random mutation can result in new alleles of a gene. Many mutations are harmful but, in certain environments, the new allele of a gene might benefit its possessor, leading to increased reproductive success. The advantageous allele is inherited by members of the next generation and over many generations, the new allele increases in frequency in the population.

Question 48

Anatomical adaptations

Question 49

Physiological adaptations

Question 50

Behavioural adaptations

Question 51

Courtship behaviour

Question 52

What are groups called in phylogenetic classification?

Answer 52

Each group is called a taxon (plural is taxa).

Question 52

Phylogenetic classification

Answer 52

Arrange species into groups based on their evolutionary origins and relationships. Using a hierarchy in which smaller groups are placed within larger groups with no overlap between groups.

Question 53

What is the order of the heirarchy comprising the taxa?

Answer 53

Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species.

Question 54

Acronym for heirarchy of taxa

Answer 54

Do Keep Ponds Clean Or Frogs Get Sick

Question 55

Binomial classification

Answer 55

A formal system of naming species of living things by giving each a name composed of two parts, their Genus and Species

Question 56

Definition of species

Answer 56

Groups of organisms which are able to produce fertile offspring

Question 57

Definition of species richness

Answer 57

A measure of the number of different species in a community.

Question 58

Index of diversity

Answer 58

The relationship between the number of species in a community and the number of individuals in each species.

Question 59

Farming techniques which reduce biodiversity

Question 60

Conservation