mitosis and meiosis study guide

sister chromatids

Identical copies of a chromosome, connected by a centromere, that are formed during DNA replication in preparation for cell division.

homologous chromosomes

Chromosome pairs, one from each parent, that are similar in shape, size, and genetic content.

chromatin

The material consisting of DNA and proteins that make up chromosomes, which condenses to form visible chromosomes during cell division.

centromere

The region of a chromosome where sister chromatids are joined and which plays a crucial role during cell division, serving as the attachment point for spindle fibers.

spindle fibers

Protein structures that form during cell division to help separate chromosomes.

cleavage furrow

The indentation that begins to form during cytokinesis in animal cells, where the cell membrane pinches inward to separate the two daughter cells.

cell plate

A structure that forms in plant cells during cytokinesis, serving as a precursor to the new cell wall between the two daughter cells.

cells that undergo mitosis

are somatic or body cells, which divide to produce two genetically identical daughter cells.

cells that dont undergo mitosis

are primarily germ cells, which undergo meiosis instead of mitosis, leading to the formation of gametes with half the number of chromosomes.

interphase

The stage of the cell cycle where the cell prepares for division, consisting of G1, S, and G2 phases, during which DNA is replicated and the cell grows.

g1

the first phase of interphase, where the cell grows and synthesizes proteins and organelles in preparation for DNA replication.

s

The phase in interphase where DNA synthesis occurs, resulting in the replication of chromosomes.

g2

The second phase of interphase following S phase, where the cell continues to grow, produces proteins, and undergoes preparations for mitosis.

prophase - mitosis

The first stage of mitosis, during which chromatin condenses into visible chromosomes, the nuclear envelope begins to break down, and spindle fibers form.

metaphase - mitosis

The second stage of mitosis, where chromosomes align at the cell's equatorial plane, and spindle fibers attach to their centromeres.

anaphase - mitosis

The third stage of mitosis, during which sister chromatids are pulled apart towards opposite poles of the cell by the spindle fibers.

telophase - mitosis

The final stage of mitosis, during which the separated chromosomes reach the cell poles, the nuclear envelope re-forms around each set of chromosomes, and the chromosomes begin to de-condense back into chromatin.

cytokinesis - mitosis

The final phase of cell division where the cytoplasm divides, resulting in two distinct daughter cells, each with a complete set of chromosomes.

if a cell has 28 chromosomes and undergoes mitosis, how many chromosomes will be in each of the 2 new daughter cells?

Each daughter cell will have 28 chromosomes, as mitosis maintains the chromosome number.

why do cells undergo mitosis

for growth, repair, and asexual reproduction, ensuring each daughter cell receives an identical set of chromosomes.

what phase of the cell cycle do cells spend the majority of their time in

Cells spend the majority of their time in interphase, which consists of G1, S, and G2 phases, preparing for mitosis.

what mechanisms do we have in place if a mutated cell gets past the checkpoints

Cells can employ mechanisms such as apoptosis, DNA repair pathways, and checkpoints that monitor and respond to DNA damage to prevent the proliferation of mutated cells.

apoptosis

a programmed cell death mechanism that eliminates damaged or mutated cells, preventing them from proliferating.

zygote

the fertilized egg formed when a sperm cell and an egg cell unite, marking the beginning of a new organism's development.

purpose of meiosis

to reduce chromosome number and generate genetic diversity through sexual reproduction.

how many diploid chromosomes do humans have in one cell

Humans have 46 diploid chromosomes in one cell, organized in 23 pairs.

how many haploid chromosomes are in one cell

Humans have 23 haploid chromosomes in one cell, which are found in gametes (sperm and egg cells).

diploid cells

Cells that contain two complete sets of chromosomes, one from each parent.

haploid cells

are cells that contain a single set of chromosomes, which is half the number of diploid cells. In humans, this constitutes 23 chromosomes.

what cells are haploid and diploid in

human reproduction cells

which cells undergo meiosis

are the germ cells, including sperm and egg cells, that undergo meiosis to produce haploid gametes.

how many times does meiosis divide

Meiosis divides twice, resulting in four haploid cells.

similarities between mitosis and meiosis

Both processes involve cell division, replicate DNA, and have similar stages such as prophase, metaphase, anaphase, and telophase.

differences between mitosis and meiosis

Mitosis results in two identical diploid cells, while meiosis leads to four genetically diverse haploid gametes. Additionally, meiosis includes two rounds of division and genetic recombination.