Biology CH 8 part 2

in meiosis

haploid gametes are produces in diploid organisms - 4 gametes are produces interphase is followed by two consecutive divisions, meiosis I and meiosis II

fertilization, zygote

haploid sperm fused with a haploid egg during ______ to form a diploid ______

trisomy

having 3 of a chromosome instead of 2

meiosis I

homologous chromosomes separate

haploid

human gametes are _____ having only one set of chromosomes -- only have 1/2 (23) becyase they have to meet with other 23

diploid

humans are ____ organisms; their somatic cells contain two sets of chromosomes --2 complete sets of chromosomes from mom/dad

2

humans have ___ sex chromosomes which determine your gender

mitotic spindle

in nondisjuction, the ____ ____ grabs the wrong number of chromosomes

down syndrome

is a well known example of nondisjuction also called trisomy 21 individual has extra chromosome 21

karyotype

is an imagine that reveals an orderly arrangement of chromosomes

random fertilization

is another way we get genetic variation but doesnt occur during meiosis

4

meiosis starts with one cell, and ends with ___ celss

70 trillion

more than_____ different possible chromosome combination

variable

offspring produces from sexual reproduction are genetically identical or variable

anti codons

on top

genetic variation

produces offspring that contain a unique combination of genes from the parents

human somatic cell

regular cell in your body skin, kidney, liver, heart has 46 chromosomes (2 sets of 23)

meiosis

1/2 the # of chromosomes 1/2 from mom/dad -uses this to make sperm and egg(sex cells)

asexual reproduction

___ ____ conveys an evolutionary advantage when plants are sparsley distributed or superbly suited to a stable enviroment

sexual reproduction

___ ____ may convey an evolutionary advatage by speeding adaption to a changing enviroment or allowing a population to more easily rid itself of harmful genes

mitosis, diploid

_____ uses one division and produces two ____ cells

meiosis, haploid

______ uses two divisions and produces four _____ cells

prophase I

crossing over occurs during _____. homologoys chromosomes exhancge genetic info results in 4 gametes that are all genetically different

alleles

different versions of the same genes

gametes

genetic variation is produced in the ____. Includes independent assortment and crossing over

meiosis II

sister chromatids separate

Nondisjuction

something goes wrong, disorder, syndromes members of a chromosome pair fail to separate during anaphase producing gametes with an incorrect number of chromosomes

codons

the bottoms,in threes

what happens when errors occur in meiosis

the gametes get the wrong number of chromosomes

what are gametes

they are sex cells (sperm and egg, egg and pollen) in humans 23 chromosomes, in meiosis half # of parent chromosomes

Sexual reproduction

uses meiosis and fertilization

autosomes

what all of our other chromoses that arent sex chromosomes are called --- all regular chromosomes except ones that deal with gender

crossing over, independent assortment

what are the two main processes responsible for producing genetic variation that occur during meiosis?

somatic cell

what do we call a regular body cell

Metaphase I

which stage of meiosis has the side by side orientation of each homologous pair of chromosomes is a matter of chance

haploid, diploid

your gametes are ____ meaning they have only one set of DNA, whereas all your body cells are ___ meaning they have two sets of DNA