exam 3 bioprinc

What type of cell division is involved in sexual reproduction?

Meiosis

What type of cell division is involved in asexual reproduction?

Mitosis

What is sexual dimorphism?

The phenomenon where males are larger or more colorful to compete for females.

What is hermaphroditism?

An individual functions as both male and female.

What is sequential hermaphroditism?

An individual changes sex during its lifetime.

What is protogynous hermaphroditism?

A female first becomes male second.

What is protandrous hermaphroditism?

A male first becomes female second.

What is fission in asexual reproduction?

Breaking into two individuals.

What is budding in asexual reproduction?

Individuals split off or bud off from the parent.

What is fragmentation in asexual reproduction?

The body is in several fragments and regenerates missing parts.

What is parthenogenesis?

A female forms another individual that is genetically a clone without needing a male.

What is the genetic composition of female ants?

Diploid (2n)

What is the genetic composition of male ants?

Haploid (n)

What are the advantages of asexual reproduction?

Reproduce without mates, have numerous offspring quickly, perpetuate successful genotypes, and grow faster.

What are the advantages of sexual reproduction?

Genetic diversity, although it grows slower.

What is spermatogenesis?

The formation of sperm through meiosis.

What is the role of the SRY gene?

It is present on the Y chromosome and produces testosterone.

What is oogenesis?

The production of ova from oogonia.

How does oogenesis differ from spermatogenesis?

Oogenesis has unequal cytokinesis, forms polar bodies, and has long resting periods.

What hormones are involved in the hormonal control of spermatogenesis?

Gonadotropin releasing hormone (GnRH), follicle stimulating hormone (FSH), and luteinizing hormone (LH).

What occurs during ovulation?

A primary oocyte finishes meiosis 1 and leaves the ovary as a secondary oocyte.

What are the phases of the menstrual cycle?

Menstrual phase, proliferative phase, ovulation, and secretory phase.

What are the phases of the ovarian cycle?

Follicular phase, ovulation, and luteal phase.

What is the fast block to fertilization?

Depolarization of the egg membrane.

What is the cortical reaction in fertilization?

The second block to prevent polyspermy.

ploidy

the number of sets of chromosomes in the cells of an organism

haploid (n)

unpaired chromosomes consisting of one complete set of DNA

diploid (2n)

paired chromosomes consisting of two complete sets of DNA

homologous chromosomes

pair of chromosomes; one from mom one from dad; same types of genes in same location

alleles

code for different versions of the same gene

duplicated chromosomes

when DNA is replicated, a chromosome makes an exact duplicate of itself

centromere

two identical copies of chromosome are connected at the centromere (chromatids)

meiosis

cell division in sexually reproducing organisms that unpair chromosomes in reproductive cells

what ploidy is needed for meiosis?

diploid (2n)

how many divisions are in meiosis?

two

what is the end result of meiosis?

four genetically different haploid (n) daughter cells with half the number of chromosomes of the original parent cell (gametes)

what are the goals for meiosis?

produce gametes in animals; separate paired chromosomes; create genetic variation

meiosis for sexual reproduction

egg (23 chromosomes) sperm (23 chromosomes)= fertilized zygote (46 chromosomes in 23 pairs) = embryo (46 chromosomes in 23 pairs)

karyotype

map of chromosomes in a cell

how many chromosome pairs do humans have in each cell?

23 homologous pairs (diploid 2n)

how many chromosome do humans have?

46 chromosomes (diploid 2n)

what is the ploidy of the human gamete?

haploid (n)

what are the four phases of mitosis and meiosis? (PMAT)

prophase → metaphase → anaphase → telophase

interphase

g1: cell grows; s: dna replication; g2: necessary proteins synthesized

prophase 1

chromatin begins to condense into chromosomes; homologous chromosomes pair up (tentrad); microtubules and spindle apparatus form; microtubules attatch to kinetochores at centromeric regions; crossing over occurs at chiasmata

crossing over

exchange of genetic info between a homologous pair of chromosomes (not chromatids)

where does crossing over occur?

prohase 1

which points does the exchange of genetic info occur?

chiasmata

metaphase 1

tetrads arrange in center; each chromosome of a tetrad is attached to a microtubule; independent assortment

independent assortment

random alignment of chromosomes in the center that causes many different possible combinations

anaphase 1

sister chromatids remain attached; homologous chromosomes separated

telophase

each half of cell has a complete set of chromosomes; cytokinesis splits to create two daughter cells

interkinesis

stage between meiosis 1 and meiosis 2

meiosis 2

two cells produced from meiosis 1 are now haploid; retains ploidy through meiosis 2 but amount of DNA is reduced by half; allows for separation of sister chromatids and production of 4 haploid daughter cells (gametes)

prophase 2

homologous chromosomes pair up (tentrad); microtubules and spindle apparatus form; microtubules attatch to kinetochores at centromeric regions; crossing over occurs at chiasmata

metaphase 2

tetrads arrange in center; each chromosome of a tetrad is attached to a microtubule; independent assortment

anaphase 2

microtubles pull apart chromatid

telophase

cells come apart; cytokinesis splits them apart and become chromatin; create four grandaughter cells