UNIT 1- DNA and the Genome

Question 1

Prokaryote

Answer 1

Single cell organism that contains no membrane bound organelles or other specialised organelles.

Question 2

Eukaryote

Answer 2

An organism consisting of a cell or cells in which the genetic material is DNA in the form of chromosomes contained within a distinct nucleus.

Question 3

Chromatin

Answer 3

Complex of DNA and protein packed round each other.

Question 4

Nucleotides

Answer 4

Monomer units that DNA is made up of, containing a deoxyribose sugar, phosphate group and base.

Question 5

DNA Polymerase

Answer 5

Enzyme used in DNA replication, it can only add free nucleotides to the 3’ end of the newly forming DNA strand.

Question 6

DNA Ligase

Answer 6

Enzyme that joins the fragments of DNA together in the lagging strand.

Question 7

Polymerase Chain Reaction

Answer 7

A technique for the amplification of DNA in vitro.

Question 8

Taq Polymerase

Answer 8

Heat resistant enzyme used in PCR isolated from a species of Archaea.

Question 9

Transcription

Answer 9

Formation of an mRNA copy of a section of DNA.

Question 10

Intron

Answer 10

Non-coding region of DNA.

Question 11

Exon

Answer 11

Coding Region of DNA

Question 12

Mature mRNA transcript

Answer 12

Transcript formed from the splicing of primary transcript involving cutting out the introns and sealing the exons together.

Question 13

Translation

Answer 13

Process of forming a polypeptide chain according to the base sequence on mRNA.

Question 14

Pluripotent Stem Cells

Answer 14

Stem cells that can differentiate into almost any cell type (embryonic).

Question 15

Multipoint Stem Cells

Answer 15

Stem cells that are restricted to differentiating into cell types from the organ they were found.

Question 16

Missense Mutation

Answer 16

One codon of bases is changed now coding for an incorrect amino acid.

Question 17

Nonsense Mutation

Answer 17

One codon is changed into a stop codon stopping the formation of the polypeptide chain.

Question 18

Splice Site Mutation

Answer 18

A codon located at the site of a splice site is changed allowing some introns to remain within the mature mRNA transcript.

Question 19

Frameshift mutation

Answer 19

Every base is moved along one place, so every amino acid after the point of mutation is affected, often resulting in a non-functional protein.

Question 20

Chromosome Deletion

Answer 20

This is when the chromosome breaks in two and the midsection breaks out. The two remaining ends join up forming a shorter chromosome.

Question 21

Inversion

Answer 21

In this case the chromosome splits in two places and the middle piece turns through 180 degrees reversing the sequence of genes in that section.

Question 22

Duplication

Answer 22

A section of the chromosome duplicates itself causing this gene sequence to be repeated.

Question 23

Translocation

Answer 23

A section of one chromosome breaks off and joins onto another non-homologous chromosome.

Question 24

Polyploid

Answer 24

Cells with whole genome duplications are referred to as polyploid (ie. They have more than the diploid number of chromosomes)

Question 25

Vertical Inheritance

Answer 25

Inheritance from parent to offspring as a result of asexual or sexual reproduction.

Question 26

Horizontal Gene Transfer

Answer 26

Exchanging genetic information amongst members of the same generation. This occurs between prokaryotes and can happen by transformation, transduction of conjugation.

Question 27

Natural Selection

Answer 27

The non-random increase in the frequency of those specific genes which increase an organism’s chance of survival.

Question 28

Stabilising Natural Selection

Answer 28

This occurs in a stable environment and selects for the more numerous ‘average’ versions of a trait within a population, avoiding the more extreme versions.

Question 29

Directional Natural Selection

Answer 29

This occurs in a changing environment and selects for a less common version of a genetic trait within a population resulting in an increase in frequency.

Question 30

Disruptive Natural Selection

Answer 30

This occurs when two different environments or resources become available and selects for the two most extreme versions of a genetic trait resulting into the population splitting into two distinct groups.

Question 31

Sexual Selection

Answer 31

The non-random increase in the frequency of those specific genes which increase an organism’s chance of reproductive success.

Question 32

Founder Effect

Answer 32

This occurs when a small group in a population splinters off and forms a new one. The new population may have less genetic variation than the original population.

Question 33

Species

Answer 33

A group of interbreeding organisms that produce fertile offspring.

Question 34

Allopatric Speciation

Answer 34

Speciation that occurs when a population is split into two groups by a geographical barrier eg. A river or a mountain range.

Question 35

Sympatric Speciation

Answer 35

Speciation that occurs when a population is split into two sub groups by a behavioural or ecological barrier.

Question 36

Hybrid Zones

Answer 36

Area where successful interbreeding occurs and fertile hybrids can be found.

Question 37

Bioinformatics

Answer 37

The computers and statistical analyses required to compare and sort through the sequence data of an entire genome.

Question 38

Phylogeny

Answer 38

The study of molecular differences in organisms to gain information about an organism’s evolutionary relationships.

Question 39

Pharmacogenetics

Answer 39

The study of how pharmaceutical drugs might be best designed to treat individuals with particular DNA sequences.