Genetics - 10SCI

omfl get me out of here

What is mitosis?

Mitosis is a type of cell division that occurs in body cells (somatic cells) to help the body grow and repair itself. In mitosis, the cell splits into two cells with 46 chromosomes each.

What is meiosis?

Meiosis is a special type of cell division that occurs in sex cells (gametes) that creates eggs or sperms. In meiosis, the cell splits into four genetically unique gametes with 23 chromosomes each.

What are gametes?

Gametes are sex cells that allow humans to reproduce; for males they produce sperms, while females produce eggs.

What does haploid mean?

When a cell has only one set of chromosomes. (1N)

What does diploid mean?

When a cell has two sets of chromosomes; one from the mother and one from the father. (2N)

What is a zygote?

A zygote is the product of fertilization between a sperm and an egg.

What is fertilization?

When a male gamete (sperm) and a female gamete (egg) fuse together to form a zygote.

What is a chromosome?

A thread-like structure that is a very long molecule of tightly coiled DNA. It is found in a cell’s nucleus.

What does DNA stand for?

Deoxyribonucleic Acid

What is DNA made of?

The double helix or DNA polymer is built up from nucleotide monomers. DNA has a sugar phosphate backbone, while its rungs are made of base pairs (A and T, C and G).

What are the base pairs that are always together?

A and T, C and G

What are the full names of the bases A, T, C and G?

Adenine, Thymine, Cytosine and Guanine.

What is a homologous pair of chromosomes?

A pair of chromosomes that contain the same type of genes that code for the same characteristics, such as eye colour.

What is an allele?

A different version of the same gene, e.g. an allele for blue eyes or an allele for brown eyes.

What is a gene?

Genes are segments of DNA that give your cells instructions for specific traits or body functions, e.g. a gene for eye colour.

What is DNA?

A huge molecule made up of repeating units of four nucleotides and the code for a living organism or the molecular blueprint for a living thing.

What is a nucleotide?

A three-part unit made of a nitrogen compound, a sugar and a phosphate.

What substances make up a nucleotide?

Phosphate (circle), Sugar (pentagon) and Base (A,T,C, or G)

What is a homozygous pair of alleles?

If the alleles for a characteristic in a homologous pair are the same. (e.g. TT or tt)

What is a heterozygous pair of alleles?

If the alleles for a characteristic in a homologous pair are different. (e.g. Tt)

What is a dominant allele?

An allele that is always expressed even if there is only one copy present.

What is a recessive allele?

An allele that is only expressed if there are no dominant allele present.

What is a phenotype?

All the observable characteristics of an organism.

What is a genotype?

A genotype shows the alleles of an individual represented by letters. e.g. TT, tt, Tt.

What is a cell?

The basic unit of all living creatures.

What is a characteristic?

A feature passed on to offspring, e.g. eye colour.

What are bases?

An abbreviation for nitrogen-based substances found in DNA.