Genetic Defenitions

Question 1

What is a nucleus

Answer 1

A part of the cell that contains chromosomes

Question 2

Define chromosome

Answer 2

• Thread-like structure of DNA and protein found in the nucleus of cells
• Humans typically have 46 in each cell of the body made up of 22 paired chromosomes and two sex chromosomes.
• People usually have two copies of each chromosome one from Mum (egg) and the other from dad (sperm)

Question 3

Define homologous chromosomes

Answer 3

Having the same structural features (length) and pattern of genes

Question 4

Define karyotype

Answer 4

Photo of a single chromosome, cut out and arranged according to their size

Question 5

Define gene

Answer 5

Short length of DNA that carries the genetic code for a particular trait/ characteristic or cell activity

Question 6

Define allele

Answer 6

• Different forms of the same gene- they can be dominant or recessive
• An individual inherits two alleles one from each parent
• If two alleles are the same, the individual is homozygous (AA, aa)
• If alleles are different, the individual is heterozygous (Aa)

Question 7

Define base

Answer 7

Parts of DNA involved in pairing cytosine, guanine, adenine, and thymine

Question 8

Define nucleotide

Answer 8

Forms the basic structural unit of DNA composed of a sugar molecule, a phosphate group and a base

Question 9

Define DNA

Answer 9

• A molecule that carries genetic information to the next generation, and determines phenotype
• What do you need in a made up of two length strands that wind around each other to resemble a twisted ladder a.k.a. ‘double helix ‘
• each strand has a backbone made of alternating sugar and phosphate groups

Question 10

Define trait

Answer 10

A genetically determined characteristic

Question 11

Define variation

Answer 11

Differences between organisms within a population - can be continuous or discontinuous

Question 12

Define mitosis

Answer 12

Sound of vision, body cells for growth and repair. produces two new cells, genetically identical to each other and to the parent cell

Question 13

Define meiosis

Answer 13

Cell division in testes and ovaries, producing four new cells (gametes) - genetically different to each other and to the parent cell

Question 14

Define gametes

Answer 14

Reproductive cells that contain half the number of chromosomes compared to the parent cell

Question 15

Define zygote

Answer 15

A fertilized ovum/egg that contains the full set of chromosomes

Question 16

What are somatic cells?

Answer 16

• Somatic cells are cells in the body, other than sperm and egg, which are called germ cells.
• They contain two sets of chromosomes one from each parent
• DNA mutations in somatic cells affect an individual, but cannot be passed on to their offspring
  Example: blood cells, fat cells, stem cells.

Question 17

What are germline cells?

Answer 17

• Germ-line cells include sperm and egg
• Genetic mutations in germline cells can be passed on to the offspring

Question 18

What is a genetic mutation?

Answer 18

• It is a permanent change in the DNA sequence of an organism
• Mutations can result from errors in DNA replication