week 12 chapters

Question 1

for single-celled organism,

Answer 1

cell division is reproduction

Question 2

in asexual reproduction

Answer 2

a multicellular organism simply sets aside a subpopulation of its cells to give rise to a new individual organism or organisms.

Question 3

asexual reproduction can be done by

Answer 3

starfish, strawberries

Question 4

sexual reproduction is

Answer 4

biologically expensive

Question 5

the advantage of sexual reproduction lies in

Answer 5

genomic variability

Question 6

genetic info in each cell have two homologous sets:

Answer 6

maternal
and
paternal

Question 7

sexual reproduction

Answer 7

generating offspring from the union of gametes from two parents, by way of meiosis, gamete formation, and fertilization.

Question 8

whats the chance of losing a beneficial mutation

Answer 8

50%

Question 9

the vast problems with asexual reproduction is

Answer 9

very little genetic variation

Question 10

genetic variability

Answer 10

quality of a population in which members possess a variety of different forms of a given gene or genes.

Question 11

Natural selection

Answer 11

the driving force of evolution; environmental characteristics happen to favor the survival of population members having certain desirable and heritable traits.

Question 12

homologous

Answer 12

refers to a correspondence; a fundamental similarity between two items. In heredity, two information sources that have the same role but do not carry it out identically.

Question 13

genes

Answer 13

a sequence of bases within the structure of a nucleic acid, usually DNA, that code for a protein or an RNA that has a biological function.

Question 14

how many chromosomes in each cell

Answer 14

two homologous sets of 23 chromosomes, one set from each parent

Question 15

HCL1

Answer 15

chromosome 19, influences hair color

Question 16

alleles

Answer 16

a specific form of a gene; it occupies a defined position on a particular chromosome within an individual. Other individuals may have other forms of the gene at that location.

Question 17

how do genes compete?

Answer 17

you have two sets of every chromosome that are similar enough to be paired however they may be difference

the dominant gene will win out, unless both genes are unanimously indominant

Question 18

human cells chromosomes are

Answer 18

diploid, with only two homologous sets

Question 19

ploidy

Answer 19

refers to the number of complete sets of chromosomes in the nuclei of an individual’s cells. Most higher animals are diploid (two sets) except in their sex cells.

Question 20

if every human cell had 46 chromosomes and the chromosomes did not divide during mitotic division…

Answer 20

then each generation would only gain more and more chromosomes in each cell, making DNA unrecognizable and inconsistently shitty

Question 21

haploid

Answer 21

refers to a cell or an organism whose cells contain a single copy of the genome of the organism; sex cells are typically in this category.

Question 22

meiosis

Answer 22

a sequence of two cell division events that halves the number of chromosomes in the nucleus and supplies them to the sex cell in their unreplicated state.

Question 23

chromosomes are homologous sets of 23 so that…

Answer 23

…when only 50% of the chromosomes are being used for reproduction they can be properly matched with the other parents chromosomes, making up the same 46 chromosomes all over again.

Question 24

The human karyotype

Answer 24

The chromosomes in the human white blood cell nucleus can be chemically induced to condense.

The chromosomes are then cut from the photo and arranged into obvious pairs.

There are 23 pairs of chromosomes in a normal individual.

Question 25

difference between mitosis and meiosis

Answer 25

in mitosis simply replicated and divided 46 chromosomes

meiosis divided, and reconnected 46 chromosomes

Question 26

genetic recombination

Answer 26

an enzyme-driven process in which DNA strands in two homologous chromosomes are broken and rejoined so that segments of the two chromosomes are physically switched.

Question 27

meiosis is a series of

Answer 27

two successive cell divisions with no DNA replication between them; the result is half the number of chromosomes per cell nucleus in egg or sperm cells.

Question 28

In the first meiotic division,

Answer 28

a member of each homologous pair of chromosomes is pulled into each daughter cell during anaphase, hence the chromosome number per cell is halved.

Question 29

In the second meiotic division,

Answer 29

sister chromatids—the products of the original DNA replication prior to meiosis—are separated leaving daughter cells with unreplicated chromosomes.

Question 30

primary germ cells

Answer 30

those cells in the early embryo whose daughter cells will ultimately differentiate into sex cells, that is, sperm and ova.

Question 31

during your third week

Answer 31

the 50 primary germ cells develop on your posterior yolk sac

Question 32

gonadal ridge

Answer 32

mesodermal tissue between the somites and lateral mesoderm that develops into gonadal tissue, either ovaries or testes.

Question 33

ovaries

Answer 33

a female reproductive organ whose tissues secrete hormonal signals and both house and mature developing ova.

Question 34

testes

Answer 34

a male reproductive organ whose tissues secrete hormonal signals and mature developing sperm cells.

Question 35

gametes have one purpose

Answer 35

fertilize or die

Question 36

pregastrulation

Answer 36

mesodermal cells not yet defined

Question 37

oogonia

Answer 37

an immature, diploid, pre–ovum cell that arises from primary germ cells by mitosis.

Question 38

oocyte will not complete meiosis

Answer 38

till the time of fertilization

Question 39

oocytes remain in prophase 1 until

Answer 39

the child matures sexually

Question 40

gametes

Answer 40

a sex cell; a cell that has both completed meiosis and differentiated morphologically such that it can participate in the process of fertilization.

Question 41

male germ cells come from spermatogonia:

Answer 41

an immature, diploid, pre–sperm cell that arises from primary germ cells by mitosis.

Question 42

if the cell dividing is a zygote

Answer 42

then a unique individual will result

Question 43

(FSH)

Answer 43

synthesized and secreted by the pituitary gland; it regulates critical aspects of the maturation of sex cells.

Question 44

levels of follicle-derived estrogen in the bloodstream is signaling

Answer 44

the pituitary gland that follicular development is proceeding normally in the ovary.

Question 45

This sudden elevation of LH levels in the bloodstream causes the most mature follicle in the ovary to rupture at its surface. This rupturing is called: ovulation

Answer 45

a process in which a mature ovum or egg cell ruptures from a follicle next to the surface of the ovary such that the ovum leaves the ovary and enters the fallopian tube.

Question 46

The human menstrual cycle is guided over a 28-day period by

Answer 46

the hormones FSH and LH released from the pituitary gland and estrogen and progesterone generated by the follicle.

Question 47

he ovulated ovum is caught by fimbriae extensions of the fallopian tubes, which

Answer 47

carry it toward swimming sperm cells and then toward the uterus, where it implants.

Question 48

endometrium

Answer 48

within which a fertilized conceptus can develop.

Question 49

Once a follicle ruptures,

Answer 49

it converts into a yellow conglomeration of cells called a corpus luteum; this begins to secrete the hormones estrogen and progesterone, which help maintain the uterus in a receptive state for implantation of a conceptus.

Question 50

The menstrual cycle functions repeatedly over a period of from

Answer 50

30 to 40 years

Question 51

The human ovarian follicle is an excellent example of a group of cells that exist only for

Answer 51

the sake of the oocyte cell within them.