chp 3.1 chromosones and inheritance

inheritance and mitosis

in what organisms was fertilization fist studied

frogs and urchins

what elements are contributed equally by maternal and paternal gametes

egg and sperm nuclei

what is mitosis

when chromosomal threads split lengthwise in two before cell division, results in daughter cells.

what is meiosis

when nuclear division generates gametes, egg or sperm cells contain half the number of chromosones

what in teh nucleus contains hereditary material

chromosones

define gametes

specialized cells (eggs and sperm) that carries genes between generations

define a chromosome

self replicating DNA/protein complexes in the nucleus that contains genes

what is mitosis

the process of division that produces daughter cells that are genetically identical to each other and parent cells

what is meiosis

cell division of diploid gamete that results in four haploid daughter cells each with half the chromosomes of parent cell

what are the two stages of cell division in meiosis

first division, pairs of homologous chromosomes split into two different daughter cells. in second division, chromatids of each homolog segregate into two different daughter cells.

what is a zygote

2n cell formed by fertilization

what is a centromere

the location at which sister chromatids are attached to eachother

what is a meta centric chromosome

centromere is more or less in the middle

what is a acrocentric chromosome

centromere close to an end

what is a sister chromatid

two identical halves of a chromosome

what is a homologous chromosome (aka homologs)

chromosomes that match in shape, size and banding

what is a nonhomologous chromosome

chromosomes that carry unrelated genetic info and appear in different colour

what is a karyotype

arrangement of homologous pairs of chromosomes, decreasing in size and stained to produce banding.

what is aneuploidy

a condition where an organism is missing or additional chromosomes

what is amniocentesis

a method in which a needle is inserted into amniotic sac obtaining fetal cells to analyze for certain genotypes

what is NGS (next gen sequencing)

non invasive testing of cell-free fetal DNA that circulates through maternal bloodstream

what is located on chromosomes that travel with them during cell division

genes

what is chromatin

when chromosomes resemble a fine tangled string inside the nucleus

what is a ribosome

organelles that function in protein synthesis

what are nucleoli

darker areas of chromatin that eventually develop into ribosomes

what is the nuclear envelope

membrane separating nucleus from cytoplasm

what are the three phases of interphase in mitosis

G1, S, G2

how long and what occurs in G1

last from birth of new cell to beginning of chromosome replication, highly varied through species. achieves most of its growth in this phase to make materials needed to function.

what occurs in S phase

DNA synthesis, chromosomes duplicate to produce identical sister chromatids

what occurs in G2

protein synthesis before mitosis, sister chromatids become homologous chromosomes

what is G0

a resting form of G1 in which cells do not divide again during lifetime

what is a centriole

short cylindrical structures in animal cells that help to organize microtubules

centrosome

organizing center for microtubules made of 2 centrioles at right angles, serves as pole of mitotic spindle

what is the mitotic spindle

microtubule based, bipolar structure that forms during mitosis to separate sister chromatids

what do plants and fungi not have that animals have

centrioles

what happens in prophase (mitosis)

chromosomes condense and become visible, move apart towards opposite poles. nucleoli begin to disappear

what happens in prometaphase (mitosis)

nuclear envelope breaks down allowing microtubules from centrosomes invade nucleus. sister chromatids attach to microtubules from opposite poles

what happens in metaphase (mitosis)

chromosomes align on metaphase plate with sister chromatids facing opposite poles

what happens in anaphase (mitosis)

sister chromatids detach at centromere and pulled towards opposite poles

what happens in telophase (mitosis)

nuclear membranes and nucleoli re form around chromatin, as spindle fibres disappear

what happening in cytokenisis (mitosis)

cytoplasm divides splitting elongated parent cell into two identical daughter cells

state the order of mitosis phases

prophase, prometaphase, metaphase, anaphase, telophase, and cytokenisis

what are contractile rings

thread like protein mechanisms that creates cleavage furrow that divides cells during cytokinesis

how does a tumor develop

when normal checkpoints on cell divisions fail, cells begin to divide uncontrollably and accumulate mutations

what are somatic cells

cells that make up the vast majority of an organism tissues

what are germ cells

specialized cells that undergo meiosis producing gametes

explain what happens in meiosis one vs meiosis two

1, two daughter nuclei are formed. 2, each of the two daughter nuclei divides into four nuclei