AP Biology - Chapter 8: The Cellular Basis of Reproduction and Inheritance

asexual reproduction

process by which a single parent reproduces by itself

sexual reproduction

process by which a sperm and egg join to reproduce

budding

a type of asexual reproduction where a group of cells form a bud and break away from the original organism to form a clone

List the 3 parts of the cell theory

All living things are composed of at least one cell; The cell is the smallest unit of life; Cells arise only from the division of pre-existing cells

binary fission

a type of asexual reproduction done by prokaryotes where a cell first replicates its single chromosome, slowly separating as the cell membrane and wall expand, eventually splitting and dividing into two daughter cells

How many chromosomes do prokaryotes have, and what shape?

one circular chromosome

T/F: Genes are bigger than chromosomes

false; each chromosome has many genes

Which protein is attached with a DNA chain in chromosomes?

histone proteins

When is the only time chromosomes are visible?

during cell division, otherwise, they stay as chromatin

chromatin

loosely coiled DNA fibers (like spaghetti)

interphase

first stage of the cell cycle; DNA and organelles are duplicated; prepare for division

G1 (gap 1)

cell growth, protein production

S (synthesis)

all DNA is copied

G2 (gap 2)

organelles are replicated

What does DNA exist as during interphase?

chromatin

What are the 4 phases of mitosis?

prophase (and prometaphase), metaphase, anaphase, telophase/cytokinesis (PMAT)

What is the longest phase of mitosis?

prophase

prophase (mitosis)

chromatin condenses into chromatids, sister chromatids join at the centromere, nucleolus disappears, centrosomes (centrioles) start to produce spindle fibers and move towards poles

centrosomes

pair of centrioles; where spindles come from

centromere

attachment site of sister chromatids

prometaphase (late prophase) (mitosis)

nuclear membrane breaks down, spindles attach at kinetochores, spindles move chromatid pairs to metaphase plate

kinetochore

where spindle fibers attach to the centromer

metaphase plate

an imaginary line in the middle of the cell where spindle fibers pull chromatid pairs to

metaphase (mitosis)

chromosome pairs and centromeres line up at metaphase plate

anaphase (mitosis)

centromeres split, spindles that are attached to chromosomes recoil and split sister chromatids apart, other spindles get longer and pull the poles apart (cell is stretched)

telophase (mitosis)

chromosomes unwind into chromatin , nuclear envelope and nucleolus form, spindles disappear, microfilaments pinch at center

cytokinesis (mitosis)

cytoplasm division; cytoplasm completely divides along cleavage furrow (in plants, cell wall divides along cell plate made of vesicles), contractile ring of microfilaments pinches cytoplasm in half, forming 2 new cells

cytokinesis in plants

vesicles containing cell wall fibers line up on the cell plate, thickening and eventually forming a new cell wall

What type of reproduction do bacteria do?

binary fission

Name 3 categories of cells that do not divide

red blood cells, nerve cells, muscle cells

anchorage

an external physical factor that causes cells to divide only when attached to a surface

density-dependent inhibition

an external physical factor that causes cells to stop dividing once they are touching each other

growth factor

an external chemical hormone (so it's a protein) secreted by cells to stimulate other cells to divide

What structure of a cell receives growth factors? Where on the cell is this structure?

receptor protein, found on cell membrane

PDGF

platelet-derived growth factor, gives the 'green light' after G1 for progression into cell cycle

Where are check points found in the cell cycle?

After G1, G2, and metaphase

G2 checkpoint

makes sure the S phase properly replicated all DNA and the G2 phase properly duplicated all organelles

M checkpoint (METAPHASE, NOT MITOSIS)

triggers sister chromatid separation/starts anaphase

cyclin-dependent kinase (cdks)

enzymes that activate or deactivate other proteins by phosphorylating them; are only activated when bound to a cyclin; entirely dependent on cyclin concentration!

cyclins

proteins that bind to Cdks; concentrations peak during mitosis and fluctuate throughout the cell cycle

MPF

Maturation (M-phase) Promoting Factor; an ACTIVE type of Cdk; created from cyclins binding to Cdks; triggers mitosis; turned off during anaphase (after degradation of cyclin)

cancer cells

divide excessively, produce tumors and their own growth factor; divide and live longer than normal cells

Why do cancer cells keep dividing uncontrollably?

the growth factor they produce signals continuous cell division, no DDI or anchoring can stop them

benign tumor

a type of tumor that is pretty much harmless and stay put

malignant tumor

a type of tumor that spreads (metastasizes) to other organs, BAD

carcinomas

malignant tumors in the skin, intestines, and colon

sarcomas

malignant tumors in muscles and bone

leukemia/lymphoma

malignant CANCER in blood tissue; cancerous malignant tumors exist in liquid form

chemotherapy

treatment of cancer with drugs

Which cells are most impacted by chemotherapy?

fast dividing cells, including cancerous cells, hair follicles, intestinal lining, and immune cells

anti-cancer drugs

all botanical (plant) extracts that prevent cell division

taxol

an anti-cancer drug that freezes mitotic spindle in metaphase (no cell division)

vinblastin and colchicine (same thing)

an anti-cancer drug that prevents any spindle formation (no cell division)

somatic cells

normal body cells; needed for growth, repair, and replacement

gametes

sex cells (sperm and egg); needed for sexual reproduction only

homologous chromosomes

chromosomes with same size, shape, gene location, and centromere location

locus

specific location of a gene on a chromosome

haploid

a cell with one complete set of chromosomes (23 total in humans); sex cells

diploid

a cell with two complete sets of chromosomes (46 total in humans); body cells

autosomes

non gender-specific chromosomes (same for males and females)

Which cell determines the sex of the offspring?

sperm

What is the DIPLOID number of this cell?

>

< <

>

2n = 4

germ cell

a cell that undergoes meiosis to become a gamete

prophase I

chromatin condenses, sister chromatids join, homologous sister chromatids join into tetrads and cross over, spindles form from centrosomes and attach to kinetochore, moving tetrads to metaphase plate

Where do homologous chromosomes cross over in their tetrad?

chiasmata

synapsis

homologous chromosomes join into tetrads

metaphase I

tetrads line up at metaphase plate

anaphase I

chiasmata separate (centromeres don't), spindle recoils, pulling tetrad pairs apart, each pair of sister chromatids move to opposite sides of cell

T/F: The separated tetrads after anaphase 1 are homologous chromosomes

FALSE!!!!!!!!!! Because the crossed over during prophase 1, they are no longer identical pairs!!

telophase I & cytokinesis

cell pinches in the middle and cytoplasm divides, each cell (there are 2 at this stage) has 1 pair of non-identical sister chromatids from each OG tetrad

PMAT II

identical to PMAT in mitosis

After meiosis...

there are 4 haploid daughter cells NOT identical to each other

spermatogenesis

production of sperm

spermatogonia

male germ cells (diploid) that divide by MITOSIS, some undergo meiosis

What do spermatogonia become after mitosis?

spermatocytes (diploid & identical)

Why do most male germ cells divide by mitosis?

Allows for the production of identical diploid germ cells so there is always a supply

What results from spermatogenesis (after meiosis)?

spermatids

What process must spermatids undergo to become sperm?

maturation

Are spermatids haploid or diploid?

haploid

spermatozoa

fancy way of saying sperm

T/F: sperm have a nucleus, mitochondria, and flagella

true

oogenesis

production of ovum (egg)

T/F: Cytokinesis in oogenesis splits cells into equal sizes, all usable eggs

false, it splits cells into 1 large ovum, a usable egg, and 3 polar bodies, which are too small and unusable

oogonia

female germ cells (diploid) that divide by mitosis; some undergo meiosis

What do oogonia become after mitosis?

oocytes (diploid & identical)

How many usable eggs are formed from a female germ cell (diploid)?

1

primary oocyte/spermatocyte vs secondary oocyte/spermatocyte

primary oocyte/spermatocyte results from mitosis and goes into meiosis, secondary oocyte/spermatocyte is after meiosis I

alleles

different variations of a gene (black hair vs blonde hair)

T/F: All genes, no matter the variation, are found in the same spots on each chromosome (same locus)

true

karyotype

photograph of chromosomes grouped in order and paired; used to detect abnormal chromosomes

non-disjunction

failure of chromosomes to separate equally, can lead to trisomy

trisomy

an extra chromosome

trisomy 21

down syndrome, 3 chromosome 21s instead of 2

XYY

super male

XXX

super female

XXY

Klienfelter's syndrome

X0

Turner's syndrome (lack of Y or a second chromosome)

T/F: As long as there is a Y chromosome, it is a male

true

What does 47 XY + 21 mean?

the individual has a total of 47 chromosomes, is a male, and has an extra chromosome 21, hence he has down syndrome

nondisjunction in meiosis I

failure of homologous pairs to separate, so spindle drags an entire tetrad to a side of the cell