Genetic Revision

Question 1

DNA

Answer 1

Blueprint/code for life

Question 2

Gene

Answer 2

A unit of inheritance. located in chromosomes

Question 3

Chromosomes

Answer 3

Packets of DNA (23 pairs)

Question 4

Homologous chromosomes

Answer 4

A matched pair of chromosomes that carry genes for the same characteristics

Question 5

Allele

Answer 5

One version of a gene, found at a specific location along a chromosomes.

Question 6

Dominant trait

Answer 6

An allele that is always expressed, even if the cell only contains one copy

Question 7

Recessive trait

Answer 7

An allele that is only expressed if two versions of it are present in a cell.

Question 8

Homozygous

Answer 8

Having two identical alleles of a specific gene.

Question 9

Heterozygous

Answer 9

Having two different alleles of a specific gene.

Question 10

Carrier

Answer 10

An individual with a recessive allele, whose effect is masked by a dominant allele.

Question 11

Genetype

Answer 11

The combination of alleles giving that appearance.

Question 12

Phenotype

Answer 12

All the observable characteristic of an organism.

Question 13

Autosomes

Answer 13

Any chromosome that isn’t a sex chromosome

Question 14

Sex chromosomes

Answer 14

They consist of X and Y chromosomes

Question 15

Punnett Square

Answer 15

A grid system that can predict possible outcomes between two individuals.

Question 16

Pedigree

Answer 16

The recorded ancestry or lineage of a person or family

Question 17

Sex-linked inheritance

Answer 17

Sex-linkage is found on the X chromosome by not on the Y. The female can be a carrier.

Question 18

Incomplete dominance or co-dominance

Answer 18

A situation where two alleles are both partially expressed, producing an intermediate phenotype

Question 19

Enzyme

Answer 19

A substance produced by a living organism which acts as a catalyst.

Question 20

Mutation

Answer 20

The changing of the structure of a gene.

Question 21

Restriction enzymes

Answer 21

These have the ability to cut DNA molecules at very precise sequences.

Question 22

Ligation

Answer 22

DNA fragments produced by using restriction enzymes may be reassessed.

Question 23

Plasmid

Answer 23

Extra bits of DNA in the nucleus. Used in genetic engineering. Circular shape

Question 24

Genetic engineering

Answer 24

A deliberate modification of the characteristics of an organism by manipulating its genetic material.

Question 25

Clone

Answer 25

An organism or cell, or group of organisms or cells, produced asexually from one ancestor or stock, to which they are genetically identical

Question 26

Transgenic organism

Answer 26

Organism that have had genes from other species inserted into their genome.

Question 27

Genetically modified organism

Answer 27

Whose genetic material has been altered using genetic engineering techniques.

Question 28

Pure-breeding

Answer 28

An organism that always passes down a certain phenotypic trait to its offspring

Question 29

Recombinant DNA

Answer 29

DNA that had been formed artificially by combining components from different organisms

Question 30

Point mutations

Answer 30

Mutagens change a single base in the DNA code

Question 31

Frameshift mutation

Answer 31

Some mutagens delete or insert bases into the DNA molecule, causing a change in the sequence of bases.

Question 32

Crossing over

Answer 32

The exchange of genes between homologous chromosomes, resulting in a mixture of parental characteristics in offspring

Question 33

Hereditry

Answer 33

The passing on of physical or mental characteristics genetically from one generation to another.

Question 34

Variation

Answer 34

A change or slight difference in condition, amount or level of something.

Question 35

Blunt end

Answer 35

A fragment of DNA resulting from the breaking of DNA molecule in which there are no unpaired bases or overhangs

Question 36

Sticky end

Answer 36

A fragment of DNA (often produced by a staggered cut on the DNA using restriction enzymes). The strands are not the same length.

Question 37

Mutagen

Answer 37

Factors may cause mutations which are known as mutagens