Biology terms for memorising level 1

Question 1

Adaptions

Answer 1

Traits/phenotypes which allow an organism to better survive in its environment

Question 2

Allele

Answer 2

An alternative version of a gene

Question 3

Ancestor

Answer 3

An organism (or species) from which other organisms (or species) have evolved

Question 4

Amino acids

Answer 4

The building blocks of proteins

Question 5

Antiparallel

Answer 5

The two strands of a DNA molecule run in opposite directions

Question 6

Asexual reproduction

Answer 6

Requires only one parent. All offspring are genetically identical to the parent

Question 7

Bases

Answer 7

A, T, G, C

Question 8

Chromosome

Answer 8

A long strand of DNA containing a specific set of genetic information

Question 9

Complementary base pairs

Answer 9

A:T and G:C. Ensures the genetic code is replicated correctly during DNA replication

Question 10

Crossing-over

Answer 10

Swapping of DNA between homologous chromosomes during the meiosis process. Increases genetic variation

Question 11

Deoxyribonucleic acid (DNA)

Answer 11

A molecule that carries the genetic code

Question 12

DNA sequencing

Answer 12

The process of finding out the exact order of bases on a length of DNA

Question 13

Dominant

Answer 13

An allele that is always expressed when it is present. Represented using capital letters. E.g. BB, Bb

Question 14

Evolution

Answer 14

Gradual change in the genetic code of organisms over a long period of time. May result in formation of new species

Question 15

Fertilisation

Answer 15

The process where the DNA from an egg and sperm fuse together

Question 16

Gametes

Answer 16

Sex cells containing half the chromosomes of the parent (haploid cells)

Question 17

Genome

Answer 17

All the DNA in a single cell of an organism

Question 18

Gene

Answer 18

A short segment of DNA that codes for a particular protein/phenotype

Question 19

Genetic code

Answer 19

The bases of a gene are read in sets of three and each triplet codes for an amino acid, which in turn, are joined to make a protein.

Question 20

Gene marker

Answer 20

A short segment of DNA that can be used to follow inheritance of a trait (especially if it is not visible) or determine relatedness of different organisms

Question 21

Genetic variation

Answer 21

The total number of different alleles in a population of organisms

Question 22

Genotype

Answer 22

The combination of alleles for a gene: BB, Bb, bb

Question 23

Genotype ratio

Answer 23

The predicted ratio of inheritance of alleles from mating of two individuals

Question 24

Heterozygous

Answer 24

Two different alleles in a genotype: e.g. Bb

Question 25

Homologous pairs of chromosomes

Answer 25

Two chromosomes in a cell with the same genes on them. One chromosome is inherited from each parent

Question 26

Homozygous

Answer 26

Two alleles in a genotype are the same: e.g. BB or bb

Question 27

Independent segregation

Answer 27

Homologous chromosomes line up at random and independently or other homologous chromosomes during the process of meiosis

Question 28

Karyotype

Answer 28

A picture of all the chromosomes in a cell, ordered from largest to smallest in homologous pairs

Question 29

Meiosis

Answer 29

A type of cell division which produces egg and sperm cells (gametes) with half the number of chromosomes of the parent cell

Question 30

Mutation

Answer 30

A permanent change in the DNA

Question 31

Offspring

Answer 31

The resulting individuals of reproduction

Question 32

Pedigree chart

Answer 32

A branching tree diagram that tracks alleles/traits being passed through a family

Question 33

Phenotype

Answer 33

How a gene is expressed as a protein/phenotype/trait

Question 34

Phenotype ratio

Answer 34

The predicted ratio of phenotypes of offspring of a genetic cross

Question 35

Phylogenetic tree

Answer 35

A diagram that orders organism in relationship to how closely related they are. Usually starts with a common ancestor on the far left

Question 36

Proteins

Answer 36

Polymers of amino acids that make up our traits

Question 37

Punnett square

Answer 37

A method of showing the probability of all the potential offspring genotypes and phenotypes that can occur from mating two individuals

Question 38

Population

Answer 38

Number of organisms of the same species living in a defined area

Question 39

Recessive

Answer 39

An allele that is only expressed in the phenotype when the genotype is homozygous (bb)

Question 40

Sexual reproduction

Answer 40

Reproduction involving two parents. Offspring inherit half their DNA from each parent

Question 41

Species

Answer 41

A group of organisms that can breed with each other and produce fertile offspring

Question 42

Trait

Answer 42

A feature of an organism (phenotype)

Question 43

Triplet code

Answer 43

Bases of genes are read in threes (triplets), each triplet codes for an amino acid to build a protein