Chapter 10.1-10.4

Prokaryotes cannot undergo normal cell division similar to how eukaryotes do, what do prokaryotes goes through instead?

Binary fission

What is Binary fission?

A process where a parent cell produces a pair of identical daughter cells

Why is Mitosis unnecessary to prokaryotes?

They cannot perform it due to the lack of a nucleus and chromosomes

What’s the first step in Binary fission and what occurs in it?

Bidirectional DNA replication. DNA is being copied and moved to both ends of the cell at the same time

What’s the second step in Binary fission and what occurs in it?

Cell elongation. The cell gets longer and a FtsZ protein begins to head towards the midpoint

Whats the third step in Binary fission and what occurs in it?

Chromosome and cytoplasm separation. The FtsZ forms a ring around the midpoint called a cleavage burrow and the cells begin to pinch off

Whats the fourth step in Binary fission and what occurs in it?

Septum formation. The cleavage burrow deepens into a septum and membranes begin to form

What is the last step in Binary fission and what occurs in it?

Cell division. The septum completed, which causes the cell to pinch into two daughter cells and the ftsZ protein is dispersed throughout the cytoplasm

What is a genome?

It is all of the genetic information inside a cell

How are the genomes in prokaryotes?

The genome is double stranded and is typically in a circle formation called a plasmid

How are the genomes in eukaryotes?

The genome is comprised of several double stranded DNA bounded with proteins to form chromosomes

What are somatic cells?

They are body cells with 46 chromosomes that is made up of 23 identical pairs

What are two sets of chromosomes called?

A diploid

What are is gamete?

They are sex cells that contain one set of 23 chromosomes

What is one set of chromosomes called?

A haploid

What happens if one set of chromosomes pairs with another?

They make a diploid organism for a total of 46 chromosomes

How are chromosomes formed into? (Part1)

DNA double helixes wrap around histones to make nucleosomes. These nucleosomes wrap around each other and form radial loop domains

How are chromosomes formed into? (Part2)

The radial loop domains loop around each other to make heterochromatin. The heterochromatin are condensed even further into chromosomes

What are homologous pairs?

They are matched pairs of chromosomes in a diploid organism that are the same length as each other

What does every chromosome have?

Two chromatids connected by a centromere

What are each arm of a chromatid called?

a long arm + a short arm)

How many chromatids do chromosomes have

two chromatids

What is a locus?

The physical location of a gene within chromosomes

What are karyotypes?

They are an individuals chromosome number and appearance (which includes the size, banding patterns, and centromere position)

How are karyotypes used?

They are used to tell how chromosomes look like and are organized by the type of chromosomes they are

What is the cell cycle?

It is an ordered events with checkpoints and stopping points that involves cell growth and cell division, which produces two new daughter cells

What are three parts in the cell cycle?

Interphase, mitosis, and cytokinesis

What is interphase?

The phase that prepares the cell to begin cell division and makes up most of the cell cycle

What are the three different components interphase is broken into?

The G1 phase, S phase, and G2 phase

What occurs in the G1 phase?

The cell prepares to undergo growth, with protein synthesis occurring and cell materials being copied

What occurs in the S phase

DNA replication and the replication of the centrosome occurs

What is a result of DNA replication?

Two identical copies of each chromosome attached at the centromere

What occurs in the G2 phase

Further preparation and protein synthesis occurs, with the macromolecules needed for cell division being made

What is Mitosis?

It a series of phases that result in the division of the cell nucleus

What is the first phase of mitosis and what occurs in it?

Prophase. Chromosomes are condensed, spindle fibers form from centrosomes that are moving towards the opposite sides of the cell and the nuclear envelope breaks down

What is the second phase of mitosis and what occurs in it?

Prometaphase. The centrosomes are at the opposite sides of the cell, the chromosomes are condensed more, microtubules form from spindle fibers and kinetochores appear in centromere of chromosomes

What is the third phase of mitosis and what occurs in it?

Metaphase. The chromosomes and microtubules are lined up at the metaphase plate and ready to be pulled apart

what is the fourth phase of mitosis and what occurs in it?

Anaphase. The chromosomes are pulled apart towards tge opposite side of the cells

What is the fifth phase of mitosis and what occurs in it?

Telophase. The chromosomes are fully separated and the nuclear envelope begins to reform to contain the DNA, the chromosomes also begin to decondense and microtubules start to break down

What is the last phase of mitosis and what occurs in it?

Cytokinesis. The cells are separated through either cleavage furrow or cell plate that results in two identical cells called daughter cells

What are the two different ways cytokinesis can occur depending on the cell?

By cleavage furrow in animal/bacteria cells, and cell plate in plant cells

What happens during Cleavage furrow in cytokinesis for anima/bacteria cells?

The cleavage furrow deepens, causing the cells to get further apart until the pinch off each other

What happens during cell plating in cytokinesis for plant cells?

Golgi vesicles begin to fuse with each other and create a cell plate, forming into a new cell wall that separates the cells

What are the three major checkpoints that regulate cell growth?

G1, G2, and M checkpoint

where does the G1 checkpoint happen and what occurs in it?

It happens at the end of the G1 phase before the S phase, DNA damage is checked by enzymes to make sure everything is good

where does the G2 checkpoint happen and what occurs in it?

It happens at the end of the G2 phase before mitosis, the chromosomes are checked to see if they’re accurately duplicated. If there’s a problem of chromosome duplication, the cell will die

where does the M checkpoint happen and what occurs in it?

It happens in the middle of mitosis in metaphase, the microtubules are checked to see if they are fully aligned and if the chromatids are attached correctly to them

What is the G0 checkpoint and where does it happen?

Its when the cell is in a quiescent (inactive) phase and the cell are not undergoing cell division, it occurs after mitosis and before G1

What occurs when there is uncontrolled cell growth in a mutated cell?

The cell outpaces the growth of normal cells and results in a tumor

What are the two main genes when talking about cell control and cell signaling?

Proto-oncogenes and tumor suppressor genes

What are proto-oncogenes?

They are genes that code for the positive cell-cycle regulators that stimulate cell division when activated (like an on switch)

What happens where there isn’t enough of proto-oncogenes?

Cell division will not happen

What happens when a proto-oncogene is mutated?

They become oncogenes

What do oncogenes do?

They move the cell cycle forward nonstop

What are tumor-suppressor genes?

They are genes that code for negative regulator proteins that prevents cell division from occurring when activated

What happens with a tumor-suppressor gene is mutated?

the cell cycle cannot be stopped from undergoing uncontrolled cell division

What is an example of tumor suppressor genes?

p53

What happens when cell division is not regulated?

There is a loss or gain of function of either proto-oncogenes or tumor suppressor genes