F215 Definitions

Question 1

Genetic Code

Answer 1

The sequence of bases in DNA that code for specific polypeptides.

Question 2

Allele

Answer 2

An alternative version of a gene.

Question 3

Locus

Answer 3

Specific position of a gene on a chromosome.

Question 4

Phenotype

Answer 4

Observable characteristics of an organism.

Question 5

Genotype

Answer 5

Alleles expressed within cells of an individual for a particular characteristic.

Question 6

Dominant

Answer 6

Characteristic in which the allele is responsible is expressed in the phenotype even in those with heterozygous genotypes.

Question 7

Codominant

Answer 7

A characteristic where both alleles contribute to the phenotype.

Question 8

Recessive

Answer 8

Characteristic in which the allele responsible is only expressed in the phenotype if there is no dominant allele present.

Question 9

Linkage

Answer 9

Genes for different characteristics that are present at different loci on the same chromosome are linked.

Question 10

Crossing over

Answer 10

Where non-sister chromatids exchange alleles during prophase 1 of meiosis.

Question 11

Continuous Variation

Answer 11

Quantitative variation where there is a wide range of phenotypic variation within the population. There are no distinct categories. It is controlled by many genes e.g height.

Question 12

Discontinuous Variation

Answer 12

Qualitative variation where there are distinct phenotypic categories. Usually controlled by one gene e.g blood type.

Question 13

Aseptic Techniques

Answer 13

Any measures taken to prevent contamination by foreign and unwanted microorganisms.

Question 14

Biotechnology

Answer 14

Industrial use of living organisms to produce food, drugs or other useful products.

Question 15

Recombinant DNA

Answer 15

A section of DNA often in the form of a plasmid which is formed by joining DNA sections from two different sources.

Question 16

Gene Therapy

Answer 16

Any therapeutic technique where the functioning allele of a particular gene is placed in cells of an individual lacking alleles of that particular gene. Used to treat recessive conditions.

Question 17

Ecosystem

Answer 17

All the living and non-living components in a specific habitat and their interactions.

Question 18

Biotic Factor

Answer 18

Living components of an ecosystem.

Question 19

Abiotic Factor

Answer 19

Non-living components of an ecosystem.

Question 20

Producer

Answer 20

Autotrophic organisms that convert light energy to chemical energy which they then supply to consumers.

Question 21

Consumer

Answer 21

Living organisms that feed on other living organisms.

Question 22

Decomposer

Answer 22

Organisms that feed on dead matter by secreting enzymes, releasing molecules, minerals and energy that then become available to other living organisms in that ecosystem.

Question 23

Tropic Level

Answer 23

The level at which an organism feeds in a food chain.

Question 24

Carrying Capacity

Answer 24

The maximum population size that can be maintained over a period of time in a particular habitat.

Question 25

Interspecific Competition

Answer 25

Competition between individuals of different species for resources.

Question 26

Intraspecific Competition

Answer 26

Competition between individuals of the same species for resources.

Question 27

Conservation

Answer 27

Maintenance of biodiversity, including diversity between species, genetic diversity within species, and maintenance of a variety of habitats and ecosystems.

Question 28

Preservation

Answer 28

Acting to keep biodiversity etc the same.

Question 29

Tropism

Answer 29

Directional growth response in which the direction of the response is determined by the direction of the external stimulus.

Question 30

Regulatory Gene

Answer 30

Makes repressor protein/transcription factor. Controls the expression of a structural gene.

Question 31

Structural Gene

Answer 31

Makes enzymes.

Question 32

Homozygous

Answer 32

Two identical alleles.

Question 33

The Biological Species Concept

Answer 33

A group of similar organisms that can interbreed and produce fertile offspring, the group is therefore reproductively isolated from others. PROBLEMS: Not all organisms reproduce sexually, members of the same species can look different, can’t be used for extinct species or fossils.

Question 34

The Phylogenetic Species Concept

Answer 34

Group of organism that have similar morphology, physiology, embryology and behaviour occupy the same ecological niche. This can be used for all organisms even if not known if species can interbreed. Closely related species have more similar DNA base sequences and molecular structures than less closely related species. Organisms with most similar DNA = clade.

Question 35

Natural Selection

Answer 35

Occurs naturally, due to selection pressures, traits selected are beneficial for survival, several traits are selected together, slower process of change.

Question 36

Artificial Selection

Answer 36

Carried out by humans, due to selective breeding, traits selected are beneficial for humans, often trait is selected on its own, faster process of change.

Question 37

Reproductive Cloning

Answer 37

Production of new individuals either naturally or artificially.

Question 38

Non-Reproductive Cloning

Answer 38

Also known as Therapeutic. Production of cloned cells to produce cells, tissues and organs to replace those damaged.