Making New Cells - Key terms + defenitions

Define chromosome

a chromosome is a thread-like structure within the cell that carries genetic material in the form of genes

Define chromatid

a chromatid is one of the two identical halves of a replicated chromosome, joined at a constricted region called the centromere

Define homologous chromosomes

two pieces of DNA within a diploid organism which carry the same genes, one from each parental source

Define centromere

point on a chromosome where mitotic spindle fibres attach to pull sister chromatids apart during cell division

Define meiosis

a special type of cell division in sexually-reproducing organisms that produce gametes, such as sperm or egg cells

Define mitosis

a process of cell duplication, or reproduction, during which one cell gives rise to two genetically identical daughter cells

Define binary fission

a type of asexual reproduction where a parent cell divides into two identical cells

Define cell division

a process in which a parent cell divides, giving rise to two or more daughter cells

Define spindle

a dynamic structure composed of microtubules, a type of cytoskeleton found in eukaryotic cells

what kind of cells does mitosis occur in?

occurs in eukaryotic cells, to make new body cells

what kind of cells does meiosis occur in?

occurs in multicellular eukaryotic organisms to produce gametes (e.g sperm and egg cells)

what kind of cell does binary fission occur in?

occurs in prokaryotes only

why does mitosis occur?

cell division for growth and repair

why does meiosis occur?

cell division for the production of sex-cells

what are homologous chromosomes?

contains the same genes but are not genetically identical

which chromosomes come from the mother?

maternal chromosomes

which chromosomes come from the father?

paternal chromosomes

Define homologues

the maternal and paternal copies of a chromosome

Define sister chromatids

the two identical copies of a chromosome created during replication

Define diploid. How many copies does a diploid have?

cell has two copies of each autosome and 2 sex chromosomes; one from each parent

Define haploid. How many copies does a haploid have?

cell contains half the amount of chromosomes - only 1 copy of each autosome and 1 sex chromosome

What symbol is diploid represented as?

(2n)

What symbol is haploid represented as?

(n)

Define an allele

different versions of the same gene that can provide different instructions

Define gene

a specific section of DNA that codes for a specific function, most often a protein

define trait

a trait is an observable characteristic of an individual

Define a dominant allele

an allele which is always expressed when it is present

Define a recessive allele

an allele which can be masked by another allele

Define genotype

an organisms genetic information

Define phenotype

a set of observable physical traits or measurable characteristics of an organism

What genotype is homozygous?

Genotype with the same alleles, can be dominant or recessive

What genotype is heterozygous?

genotype with different alleles

identify the genotype, BB or bb

homozygous

identify the genotype, Bb or bB

heterozygous