Molecular Reproduction

Question 1

What are the four stages of the cell cycle in order?

Answer 1

G1 (G0)
S
G2
M

Question 2

Describe interphase

Answer 2

Made up of stages G1, S and G2. Is the longest portion of the cell cycle, with cells spending 90% of their time there

Question 3

What is G0 stage?

Answer 3

An offshoot of the G1 stage where cells are simply living and carrying functions as normal and not dividing

Question 4

Describe G1 stage

Answer 4

aka “presynthetic gap”. Cells increase size and rate organelles for energy and protein production

Question 5

What must cells do to pass from G1 to S stage?

Answer 5

Go through a restriction point that contains criteria like having a full complement of DNA before entering S stage

Question 6

Describe S stage

Answer 6

aka “Synthesis of DNA”. Cell replicates its genetic material to have copies and gets two identical chromatids bound together by a centromere

Question 7

Describe G2 stage (CHANGE ANSWER)

Answer 7

aka “postsynthetic gap” cell has another quality checkpoint in which the cell ensures that their are enough organelles and cytoplasm for two cells. Also checks to make sure the cell DNA got replicated properly without mistakes

Question 8

Describe M stage

Answer 8

aka “Mitosis” cell ungoes mitosis stages and cytokinesis

Question 9

What are the checkpoints the cell must go through in the cell cycle?

Answer 9

First one - between G1 and S to make sure their is a full complement of DNA and it’s good before proceeding to S, aka “restriction point”
Second one - in between G2 and M which ensures there is enough organelles and cytoplasm to divide along with correct DNA

Question 10

What is p53?

Answer 10

the main protein that controls the G1/S restriction point that makes sure DNA is not damaged and gets repaired

Question 11

How to cyclins and CDKs work in the cell cycle? NEED MORE INFO IN ANSWER

Answer 11

CDKs are activated by the presence of cyclins that increase or decrease in concentration during certain parts of the cycle. CKDs and cyclins form a complex that can phosphorylate transcription factors that promote genes being transcribed for the next part of the cell cycle

Question 12

What is one of the most common mutations that cause cancer?

Answer 12

A mutation in the TP53 gene that encodes for the restriction point protein p53 will stop that protein from checking for damaged DNA and therefore the bad DNA gets replicated into new cells

Question 13

What is the definition of mitosis?

Answer 13

the process by which two identical daughter cells are created from a single cell

Question 14

What is a somatic cell?

Answer 14

any cell not involved in reproduction

Question 15

What are the phases of mitosis in order?

Answer 15

Prophase, Metaphase, Anaphase, Telophase and Cytokinesis

Question 16

Describe prophase

Answer 16

First phase of mitosis. Chromatin gets condensed into chromosomes, centrioles pairs separate and move towards opposite poles of the cell, the cell forms spindle fibers, the membrane dissolves,

Question 17

Describe metaphase

Answer 17

Second phase of mitosis. Centriole pairs are now at opposite ends of the cell. Kinetochore fibers align the chromosomes at the metaphase plate

Question 18

Describe anaphase

Answer 18

Third phase of mitosis. Sister chromatids are pulled apart by shortening kinetochores

Question 19

Describe telephase

Answer 19

Fourth phase of mitosis. “Opposite of prophase”. spindle apparatus disappears , nuclear membrane reforms, chromosomes uncoil

Question 20

Describe cytokinesis

Answer 20

Fifth phase of mitosis. Separation of the cytoplasm and organelles.

Question 21

What is reductional division vs equational division?

Answer 21

Reductional division is when you get haploid cells and equational division is when you get diploid cells

Question 22

What is meiosis?

Answer 22

A division process that create four cells through two divisions to create gametocytes

Question 23

What are the stages of meiosis?

Answer 23

Meiosis I (Including Prophase I, Metaphase I, Anaphase I, Telophase I)
Meiosis II (Including Prophase II, Metaphase II, Anaphase II, Telophase II)

Question 24

What is synapsis?

Answer 24

When homologous chromosomes come together and intertwine

Question 25

Describe how Meiosis works

Answer 25

The first round is when homologous chromosomes cross over during prophase I and the rest of the cycle is spent splitting the cell apart so that each cell now has one homologous chromosome of each kind. The next round splits the sister chromatids and now four unique cells are made.

Question 26

What is the difference between chromosomes and chromatids and chromatin?

Answer 26

Chromatin - made of DNA and histones in thin stringy fibers
Chromosomes - condensed version of chromatin which are single stranded. Becomes X shaped after replication
Chromatid - either of the two strands of a replicated chromosome that form the X. If connected by centromere they are called “sister” chromatids