Module 26 Bio Vocab.

Bio Vocabulary

Reproduction

occurs when offspring are produced by inheriting copies of chromosomes from their parents

Genes

physical locations on chromosomes that code for proteins and influence particular traits

Genotype

the set of genes an organism inherits/carries

Phenotype

the set of traits an organism expresses as a result of inherited genes (ex: hair or eye color)

Asexual

offspring inherit DNA from a single parent. Ex: binary fission in bacteria

genetic variation

range of different combinations of genes/genotypes; range of different phenotypes found among individuals

Sexual

occurs when offspring inherit DNA from 2 parents which are male and female; increases genetic variation 

diploid parent

must produce haploid cells that can combine with the haploid cells of a different parent to produce diploid cells

Parents need to combine chromosomes without what?

doubling total number of chromosomes in generation of offspring

Diploid (2n)

their cells possess two sets of chromosomes; what most plant & animal cells are

How many pairs of chromosomes do humans have?

23 pairs and (46 chromosomes in total)

haploid (1n)

When a cell contains a single set of chromosomes

Meiosis

different form of cell division which causes a diploid parental cell to divide in two stages to produce four haploid daughter cells that are genetically unique

Mitosis

produces two daughter cells that are diploid and genetically identical

Sex chromosomes:

determine if male(23XY) or female(23XX)

Autosomes:

all of the chromosomes that are not sex chromosomes

homologous chromosome

a pair of chromosomes similar in size and shape and carrying the same genes

How many pairs of homologous chromosomes do humans have

22 pairs

 karyotype

chromosomes are condensed and visible during early stages of mitosis or meiosis the homologous pairs can be displayed visually

Prophase I:

The chromosomes are duplicated prior to prophase I and are found in the form of sister chromatids

sister chromatids

chromatids connected to the same centromere.

non-sister chromatids

Chromatids that are not connected by a centromere

synapsis

a process in which homologous chromosomes move next to each other and line up perfectly gene for gene, except for the two sex chromosomes

Mammals can be:

Homologous XX or Non-homologous XY

Synapsis is important becuz ?

it allows for increased genetic diversity

Maternal homolog

chromosome inherited from mother

Paternal homolog

chromosome inherited from father

i see you

lol

chiasma (plural, chismata)

During synapsis, non-sister chromatids from the maternal and paternal homologs overlap each other in a cross-like pattern

crossing over

a process in which a chromatid can break at the chiasmata and reconnect to the other non-sister chromatid

crossing over results in what?

recombination

what is recombination?

new combination of genes

Recombinant chromatids

chromatids that have experienced crossing over

end of prophase I

nuclear envelope begins to break down and the mitotic spindles form on opposite sides of the cell

Prometaphase I

nuclear envelope is completely broken down and the meiotic spindles attach to the kinetochores of each chromosome to move them towards the middle of the cell

metaphase plate

meiotic spindles cause the homologous pairs of chromosomes to line up down the middle of the cell

gametes

male and female sex cells (egg & sperm)

diploid zygote

When 2 gametes fuse

The orientation of the chromosomes in meiosis is different than what?

metaphase in mitosis

Anaphase I

each pair of homologous chromosomes is pulled apart by meiotic spindles and each chromosome in the pair goes to opposite poles

Telophase I and Cytokinesis

The chromosomes become less condensed and the cell cytoplasm divides to create two daughter cell by cytokinesis

At the end of meiosis I each daughter cell will contain half as many chromosomes (haploid)chromosome will still be comprised of two sister chromatids

Whereas in anaphase in mitosis, the centromeres are split apart, and the sister chromatids separate

By the end of meiosis, the female produces a single large haploid cell

oocyte

polar bodies

 three small haploid cells