Biology- Genetics

Front 1

Punnett square

Back 1

Used to predict the phenotype and genotype ratios of offspring by showing how alleles combine together during fertilisation

Front 2

Cell

Back 2

The structural and functional unit of all living organisms

Front 3

Inheritance

Back 3

The passing of traits from generation to generation through the genetic code

Front 4

Chromosome

Back 4

Thread-like structures bearing genes, found in the nucleus of a cell. Visible during meiosis.

Front 5

Double helix

Back 5

The term used to describe the shape of DNA

Front 6

Dominant

Back 6

An allele that controls the phenotype regardless of what the other allele is.

Front 7

Meiosis

Back 7

Cell division producing sex cells/gametes. 4 haploid, genetically different daughter cells are produced from a diploid cell

Front 8

Nucleotide

Back 8

the building blocks of DNA, a phosphate, sugar and a base

Front 9

Testes

Back 9

The male organ that produces male gametes- sperm. Sperm is used in sexual reproduction in animals

Front 10

Karyotype

Back 10

Photograph of individual chromosomes of a cell arranged in pairs. Shows their numbers, sizes and shapes. Is used to determine sex, and identifies any chromosome mutations or abnormalities.

Front 11

Somatic mutations

Back 11

Mutations that don't occur in the testes or ovaries and aren't inheritable, like skin cancer.

Front 12

The (Complementary) Base-pairing rule

Back 12

The rule that states how the four chemicals that code DNA will only pair together like so: Adenine (A) goes with Thymine (T), and Cytosine (C) goes with Guanine (G).

Front 13

Mutation

Back 13

A permanent change in the base sequence of DNA. Can be harmful, neutral, or beneficial. Introduces new alleles to the gene pool.

Front 14

Autosomes

Back 14

Non-sex chromosomes. 22 pairs exist within humans. The last pair are sex chromosomes, XX or XY in mammals. XX is a female, XY is a male. Some people can be intersex, and can have more than 2 sex chromosomes.

Front 15

Offspring

Back 15

New individuals formed by either asexual or sexual reproduction

Front 16

Proteins

Back 16

Molecules containing amino acids. They're coded by DNA and are found in all living organisms. There are many different types with different roles, E.g, Keratin, Hemoglobin, Elastin, Collagen.

Front 17

Gene

Back 17

A section of DNA that codes for a certain characteristic

Front 18

Gametic Mutation

Back 18

A change in the base sequence of DNA which is inheritable to offspring. Caused by alteration of single base units in DNA, or deletion/insertion/rearrangement of larger sections of genes or chromosomes.

Front 19

Pedigree chart

Back 19

A chart which shows the inheritance of a specific gene or characteristic

Front 20

Allele

Back 20

An alternative form of a gene. Each characteristic has 2 alleles

Front 21

Trait

Back 21

A trait is a feature whose appearance is determined by genes, such as eye colour.

Front 22

Mitosis

Back 22

Cell division for growth and repair, producing two identical daughter cells (diploid) from one parent cell.

Front 23

Variation

Back 23

The differences between individuals

Front 24

DNA replication

Back 24

Process in which DNA makes a copy of itself. It's called semi-conservative, as the new DNA strand eventually replicated possesses one original and one newly synthesised strand of DNA. DNA in this process is uncoiled, and the hydrogen bonds are broken apart by the helicase enzyme. Free nucleotides in the nucleus base-pair to the template strand, forming the complementary strand. The enzyme polymerase re-zips DNA, and the two new strands of DNA wind back up.

Front 25

Ovaries

Back 25

Reproductive organ in females (plants and animals) that produces female gametes (eggs) via. meiosis for sexual reproduction. Unlike sperm in males which is produced in the testes throughout a males lifetime, eggs are made during the formation of the female.

Front 26

Amino acids

Back 26

DNA codes for these- they're the building blocks of proteins, and 20 different amino acids exist.

Front 27

Genetic Diversity

Back 27

The variation within the genetic code of a species, population or ecosystem.

Front 28

Sexual reproduction

Back 28

Form of reproduction involving the fusion of 2 gametes from 2 parents. Produces variation in the offspring. Good in a changeable environment.

Front 29

Recessive

Back 29

An allele that is only expressed in the offspring if the dominant allele is absent.

Front 30

Pollen

Back 30

The male gamete of plants, produced by the anther

Front 31

Zygote

Back 31

A fertilised egg. A single cell containing chromosomes from male and female gametes at the time/point of fertilisation.

Front 32

Triplet

Back 32

A sequence of three nucelotides found on a DNA strand that code for an amino acid

Front 33

Asexual reproduction

Back 33

Reproduction of identical offspring from a single parent, no gametes involved, faster and more energy-efficient than sexual reproduction, and successful in a stable environment.

Front 34

Fertilisation

Back 34

The joining of a male and female gamete to form a zygote

Front 35

DNA

Back 35

Stands for Deoxyribonucleic acid. A molecule found in the nucleus of cells which codes for an individual's genetic makeup

Front 36

Homozygous

Back 36

Possessing two identical alleles for a particular gene; true breeding when crossed with another homozygous individual with the same phenotype.

Front 37

Phenotype

Back 37

The characteristics expressed by an organism, produced by a particular genotype

Front 38

Genotype

Back 38

The combination of two alleles that a organism has for a particular gene.