Bio Lab Final

interphase

interphase

period of time between cell divisions. The nucleus appears normal, and the cell is performing it’s usual cellular functions. DNA replication occurs between G1 and G2 of interphase. chromosomes are then duplicated.

centromere

where the two sister chromatids are held together (the belt)

mitosis

nuclear division. The new nuclei receive the same number of chromosomes as the parent. (2n)

cytokinesis

when the cytoplasm divides and produces two daughter cells.

in multicellular organisms…

mitosis permits growth and repair of tissues.

in eukaryotic, unicellular organisms,

mitosis is asexual reproduction.

meiosis

part of gametogenesis, the production of gametes (sex cells). The daughter cells have half the number of chromosomes(n) as the parental cell.

MAKES 4 HAPLOID CELLS.

how does meiosis contribute to recombination of genetic material and variation among sexually producing organisms?

meiosis allows the crossing over of genetic material, and chromosomes occur in various combinations in daughter cells.

nucleoli

concentrated regions of RNA

chromatin

threadlike strands of DNA

at the start of mitosis/meiosis, the parental nucleus (surrounded by a double membrane) contains one or more nucleoli and chromatin suspended in a transparent liquid called

nucleoplasm

during division, chromatin condenses so that the chromosomes are visible, the nuclear envelop fragments, and a …

spindle appears

in mitosis, the most time is spent in…

interphase

interphase

G1 - cytoplasmic growth

S- DNA replication

G2 - structures involved in mitosis are synthesized

prophase (mitosis)

• chromosomes condense, nucleolus disappears, and nuclear envelope fragments.

• The spindle forms and the centrosomes (2 centrioles each) move to the poles.

• The duplicated chromosomes are two sister chromatids held together at the centromere

• Late prophase - the mitotic spindle occupies the space where the nucleus was.

• Microtubules stretch out in a star-like aster

• Chromosomes are attached to spindle fibers from opposite poles

mitotic spindle is made up of

poles, asters, and fibers (parallel microtubules)

metaphase

the sister chromatids are attached to the spindle and the chromosomes align at the metaphase plate (spindle equator)

anaphase

centromeres split, and sister chromatids at each chromosome separate, and move towards opposite poles of the spindle.

telophase

• the daughter chromosomes are at opposite poles, and the mitotic spindle dissolves.

• Nuclear envelope begins to reform around the daughter chromosomes at the poles.

• The chromosomes expand into chromosomes.

• cytokinesis - division of the cytoplasm

in plants, cytokinesis occurs by

cell plate formation. where Golgi body derived vesicles migrate to the spindle equator and fuse to contribute to the formation of the new cell wall.

in animal cells, cytokinesis occurs by

cleavage furrow, the cell pinches in two (boobies)

spermatogenesis

occurs in the testes, producing sperm.

• makes 4 sperm cells

oogenesis

occurs in the ovaries, producing eggs

• makes 1 egg and 3 polar bodies (nonfunctional cells that will dissolve)

meiosis reduces the number of chromosomes from

2n (diploid) to n (haploid).

meiosis - Prophase 1

duplicated chromatin condenses.

each chromosome is made of two sister chromatids

• homologues chromosomes (composed of two sister chromatids) are joined at the centromere

• Homologous chromosomes pair with each other (synapsis) and form a tetrad

• Crossing over (the end pieces flip, exchanging genetic material between two homologs)

meiosis - metaphase 1

homologous chromosomes align at the equatorial plate

meiosis - anaphase 1

homologous pairs separate with sister chromatids remaining together

meiosis - telophase 1

two daughter cells are formed with each daughter containing only one chromosome of the homologous pair

meiosis - prophase 2

DNA does not replicate, but the nuclear envelope disorganizes and the chromatin recondenses

meiosis - metaphase 2

chromosomes align at the equatorial plate

meiosis - anaphase 2

centromeres divide and sister chromatids migrate separately to each pole

meiosis - telophase 2

cell division is complete. Four haploid daughter cells are obtained

crossing over

occurs during prophase 1

during synapsis, the chromatids break and portions of chromatids bearing genes for the same characteristics are exchanged between non-sister chromatids

independent assortment

segregation of alleles into gametes is independent of the segregation of alleles for other traits as long as the genes are on different sets of homologous chromosomes

nondisjunction

when one or more pairs of chromosomes don’t separate during anaphase II.

produces gametes with too many (n+1) or too little (n-1) chromosomes and can cause trisomy or monosomy.

*

medical conditions caused by nondisjunction

• down’s syndrome - trisomy of chromsome 21

• patau syndrome - trisomy of chromosome 13

• edward syndrome - trisomy of chromosome 18

• kleinfelter syndrome - extra X chromsomes in males (XXY)

• turner syndrome - strange X chromosome dosage in females (XO, XXX)

• XXY syndrome - an extra Y chromosome in males

seminiferous tubules

where sperm formation occurs

interstitial cells

cells between the tubules, which secretes testosterone

metabolic pathways

chemical reactions that allow organisms to acquire, store, and expend energy in order to survive.

All cells transfer chemical energy stored in fuels like carbohydrates and lipids into chemical energy primarily found in the molecule

Adenosine triphosphate, ATP. Cells can then use the energy in ATP for movement, synthesis, transport, and reproduction.

Cells make ATP (from ADP + Pi) in a complex series of metabolic pathways called

fermentation and/or cellular respiration

aerobic respiration

a type of cellular respiration that depends on oxygen.

fermentation

an ATP producing process that uses organic molecules (e.g. glucose) but does not use an electron transport chain to produce the ATP.

Exergonic reactions

release excess energy that is captured by cells for thesynthesis ATP.

• favorable/spontaneous

Endergonic reactions

requires inputs of energy

• unfavorable/non-spontaneous

oxidation

loss of electrons

reduction

gain of electrons

glycolysis

glucose (6-carbon) → 2 pyruvate (3-carbon each) + Net 2 ATP

citric acid cycle

CO2, GTP, NADH, FADH2

electron transport

NADH + FADH2 + ATP + H2O

photosynthesis

the process by which light energy is captured and stored in a chemical form, usually in the form of glucose.

light dependent reactions

capture of energy by pigments such as chlorophyll and the transfer of energy though a series if redox reactions to form ATP and NADPH. The ATP and NADPH are then used in the calvin cycle (light dependent reactions), where CO2 is fixed into a chemical form and becomes incorporated into glucose.

crossing over occurs during

prophase I

alelles

located on chromosomes, and segregate during the formation of gametes during meiosis.

homozygous dominant

two dominant alelles, (AA)

homozygous recessive

two recessive alelles, (aa)

genotype

an individual’s genes

phenotype

an individual’s appearance

homozygous dominant and heterozygous individuals show

the dominant phenotype

homozygous recessive individuals show the

recessive phenotype

true breeding

all self-fertilized offspring display the same traits as the parent

When parents that were true breeders for different alleles were crossed (homozygous dominant x homozygous recessive) the offspring are

hybrids

two heterozygous parents produce a

phenotypic ratio of 3:1

law of segregation

each organism contains two alleles for each trait, and the alleles segregate during the formation of gametes. Each gamete then contains only one alelle for each trait. When fertilization occurs, the new organism has two alelles for each trait, one from each parents.

monohybrid cross

only one trait is being studied

law of independent assortment

members of an allelic pair segregate (assort) independently of members in another allelic pair. Therefore, all possible combinations of alleles can occur in gametes.

gene

A sequence of DNA that is transcribed

the structure of DNA was found by

James Watson and Francis Crick

The basic structure of genes is the same in bacteria and humans, with the only difference being the sequence od bases that make up DNA. This makes it easy …

to manipulate DNA from an organism and transform it into another.

plasmid

jellyfish gene