cell replication in eukaryotic cells

Question 1

cell replication in eurkayotic cells

Answer 1

the cell cycle in eurkaryotic is slightly more complicated than that of prokaryotics, due in part to the amount of DNA in each cell. DNA is organised into chromosomes. there are mutliple chromosomes, which must all be carefully copied. in comparison prokaryotics have 1 cicular chromosomes.

Question 2

what are the 3 distinct phases of the cell cycle

Answer 2

• interphase
• mitosis
• cytokinese

Question 2

cell cycle what happens

Answer 2

first interphase - replication of DNA of parent cell
second mitosis - organisation of chromosomes, followed by their separation into 2 identical groups at different poles of a parent cell, leading to identical nuclei
step 2 cytokinesedivision of parent cells into 2 cells through the splitting of the membrane

Question 3

step 1; interphase

Answer 3

an essential process of the cell cycle is a replication of dna, the genetic material,. Dna replication occurs during a stage of a cell known as interphase. The chromosomes are not visible in this step
* a cell spends most of it’s life in interphase
* interphase has 3 stages

Question 4

stage 1; G1 stage

Answer 4

• the cell undergoes growth increasing the cell cytosol
• the cell sythesises proteins that are needed for Dna replication
• the mitochrondria and chloroplast replicate
• near the end of this stage the cell either commits to continuing or drops off, not dividing and enters G0, which is a non dividing quiscent

Question 5

stage 2; S phase

Answer 5

• during the s stage o interphase, the parent cell synthesis or replicates it’s DNA
• at the end of the s stage, the parent cell contains 2 identical copies of it’s original DNA

Question 6

stage 3: G2 stage

Answer 6

• during G2 stage of interphase, further growth of the cell occurs in preparation for cell division.
• by the end of interphase, the cell has doubled in size.
• organelles also replicate in this stage

Question 7

(mitosis) stage 1; prophase

Answer 7

prophase; chromosomes gradually, becoming shorter and thicker, adn become visible as double stranded. the spindle forms and the nuclear membrane begins to disintegrate.

Question 7

step 2; mitosis

Answer 7

mitosis is the stage of cell division.
mitosis has 4 steps, prophase, metaphase, anaphase, telophase

Question 8

(mitosis) stage 2; metaphase

Answer 8

metaphase; stage of mitosis during which chromosomes align around the equator of a cell. (the double stranded chromosomes, also called dyads, line up around the equater of a cell.)

Question 9

(mitosis) stage 3; anaphase

Answer 9

anaphase;stage of mitosis during which sister chromatids separate and move to opposite poles of the spindle fibre within a cell. (the sister chromatids separate and are pulled to opposite eds of the spindle by the contraction of spindle fibres.)

Question 9

(mitosis) stage 4; telophase

Answer 9

telophase; stage of mitosis in which new nuclear membranes form around the separated groups of chromosomes. (a nuclear membrane forms around each separate group of single -stranded chromosomes and the chromosomes gradually decondense.

Question 10

what is the spindle

Answer 10

spindle; fine protein fibres that form between the poles of a cell during mitosis and to which chromosomes become attached.

Question 10

what is the chromotid

Answer 10

chromotid; one of 2 identical threads in a replicated DNA molecule.

Question 11

what is a centremere

Answer 11

A centromere is a constricted region on a chromosome that serves as the attachment point for spindle fibers during cell division, ensuring the correct segregation of chromosomes to daughter cells

Question 12

what is the chromatin

Answer 12

a genetic material or a macromolecule comprising DNA, RNA, and associated proteins, which constitute chromosomes in the nucleus of a eukaryotic cell.(basically a ball of DNA)

Question 13

step 3; cytokinese

Answer 13

*after the 2 new nuclei created at the end of mitosis, the cytosol and organelles, such as mitochrondria adn chloroplats, surrond each nucleus and cytokinese occurs.
* the bridge of the cytoplasm between the 2 new nuclei narrows as the plasma membrane pinches into a separate nucleus and cytoplasm for the 2 new cells.
* in plant cells a cell wall for each forms between the 2 groups of chromosomes and develop into a new cell wall for each of the ewly produced cells.

Question 14

the changes to chromosomes during mitosis

Answer 14

• individual chromosomes first become visible as double, thread like structures held together in a costricted region. each of these threads is called a chromatid and the position where they are held together is called a centromere
• the chromosomes continue to shorten and thicken, and the nuclear membrane disintergates. at the same time, the very fine protein fibres, or microtubules, in the cytosol move towards the nucleus.
• two things then happen, the centrimeles split, so that there are pairs of chromosomes, and the spindle fibres contract.

Question 14

mitosis and animal and plant cells

Answer 14

mitosis is essentially the same in plant and animal cells. the same differences that do exist are nto related to the genetic material, nor do they have an impact on a biological signifiance of the process.