Finals 2022 : Cell Cycle, Cell Differentiation, Cell Specialization

Question 1

What are some difficulties a cell faces as it increases in size?

Answer 1

1. As a cell becomes larger, it places a greater demand on DNA. More and more stress is put on DNA and eventually the DNA cannot meet all of the cell’s needs.
2. A large cell has difficulty transporting nutrients into the cell and waste out of it. As a cell becomes bigger, the volume of the cell increases. The cell needs more nutrients and produces more waste. There is not enough surface area (cell membrane) to transport things in and out of the cell fast enough to meet the needs of the cell.

Question 2

What are the main events of the cell cycle?

Answer 2

First the cell grows, goes through dna synthesis where dna gets copied, the cells than grow more and prepare for mitosis. When mitosis occurs, the original cell, now enlarged, separates into daughter cells, one enters the system and the other one repeats the cycle.

Question 3

How is the cell cycle regulated under normal conditions?

Answer 3

There is a group of proteins that regulates the phases of the cell cycle to ensure that all events needed for normal cell division take place before division of the cell begins. These “checkpoints” occur to ensure that the specific cell type divides at the right time and place. Regulation of the cell cycle also ensures that a cell completes the growth and synthesis (copying of DNA) phases so that the parent cell will divide properly into 2 new cells.

Question 4

How do cancer cells form from other cells?

Answer 4

A disruption of the regulation of the cell cycle can result in uncontrolled cell growth that may lead to cancer. (Like a Mutation)

Question 5

What are examples of specialized cells in the body?

Answer 5

• Motor neuron
• Photoreceptor
• Hair follicle cell
• Cheek cell
• Skin cells
• Heart cell
• Smooth muscle cell
• Red blood cell
• White blood cells
• Macrophage
• Alpha cell
• Beta cell
• Bone cells
• Intestinal epithelial cell

Question 6

Cell Cycle Definition

Answer 6

The process a cell goes through each time it divides.

The cell cycle consists of a series of steps during which the chromosomes and other cell material double to make two copies. The cell then divides into two daughter cells, each receiving one copy of the doubled material.

The cell cycle includes alternating patterns of cell growth and replication:

• Interphase: G1, S, G2
• Cell Division: Mitosis & Cytokinesis

Question 7

Mitosis Definition

Answer 7

The division of the nucleus of a eukaryotic cell.

Question 8

Cytokinesis Definition

Answer 8

The division of the cytoplasm.

Question 9

Stem cells Definition

Answer 9

Cells from which all other cells with specialized functions are generated.

Question 10

Interphase Definition

Answer 10

A cell spends most of its time in interphase. During interphase, the cell grows and performs its function(s). Interphase is called so because it is the “in-between” period from one cell division to the next.

Question 11

Cyclins Definition

Answer 11

Proteins that regulate passage through the check points before S, G1 and the early events of mitosis.

Question 12

Cancer Definition

Answer 12

Disease caused by an uncontrolled division and growth of abnormal cells in a part of the body.

Question 13

Cell Specialization Definition

Answer 13

Differentiation = Specialization

When individual cells become specialized in structure / function. Stem cells produce specialized cells.

The differentiation of cells results from selective gene expression.

As differentiation progresses, segments of the genetic material are either activated (turned “on”) or suppressed (turned “off”).

Question 14

Differentiation Definition

Answer 14

Differentiation = Specialization

When individual cells become specialized in structure / function. Stem cells produce specialized cells.

The differentiation of cells results from selective gene expression.

As differentiation progresses, segments of the genetic material are either activated (turned “on”) or suppressed (turned “off”).

Question 15

Bone cell Definition

Answer 15

Keep a balance between bone formation and resorption, control bone structure and function.

Question 16

Skeletal muscle cell Definition

Answer 16

They cover our skeleton and move our bones. Sometimes they are called striped muscles because they come in long dark and light bands of fibers and look striped. These muscles are voluntary because we control them directly with signals from our brains.

Question 17

Skin cell Definition

Answer 17

Any of the four main types of cells found in the epidermis. – Keratinocytes

• Melanocytes
• Langerhans
• Merkel

Skin cells grow and divide in the basement membrane. From here, the new cells get pushed up into the epidermis. Once in the epidermis, the cells no longer receive blood or nutrients. They begin the slow process of dying and sloughing off to be replaced by yet more new cells. Your outermost layer of skin is nothing but dead cells.

Question 18

Nerve cell (neuron) Definition

Answer 18

A type of cell that receives and sends messages from the body to the brain and back to the body. The messages are sent by a weak electrical current.

Question 19

Checkpoint Definition

Answer 19

A stage in the cell cycle at which the cell examines and “decides” whether or not to move forward with the division of the cell.

Question 20

G1 Definition

Answer 20

G1 Phase: Cell Growth
Cells do most of their growing during the G1 phase. In this phase, cells increase in size and synthesize new proteins and organelles. The G stands for “gap”, but G1, and G2 are actually phases of intense growth and activity.

Question 21

S Definition

Answer 21

S Phase: DNA Synthesis
The G1 phase is followed by the S phase.

During the S phase, new DNA is synthesized when the chromosomes are replicated. The cell at the end of the S phase contains twice as much DNA as it did at the beginning.

Question 22

G2 Definition

Answer 22

G2 Phase: Preparing for Cell Division
When DNA replication is completed, the cell enters the G2x phase. G2 is usually the shortest of the three phases of interphase. During the G2 phase, many of the organelles and molecules required for cell division are produced. When the events of the G2 phase are completed, the cell is ready to enter the M phase and begin the process of cell division.

Question 23

M phase Definition

Answer 23

M Phase: Cell Division
The M phase produces two daughter cells.

The process of cell division usually takes place quickly.

In eukaryotes, cell division occurs in two main stages. The first stage of the process, division of the cell nucleus, is called mitosis. The second stage, the division of the cytoplasm, is called cytokinesis. In many cells, the two stages may overlap, so that cytokinesis begins while mitosis is still taking place.

Question 24

True or False: All cells in an organism have the same set of DNA

Answer 24

True

Question 25

True or False: Different parts of the genetic instructions are expressed in different types of cells.

Answer 25

True

Question 26

True or False: Chemicals in a cell’s environment can’t affect what genes are expressed.

Answer 26

False, certain chemicals in a stem cell’s environment will determine the cell type it develops into.

Question 27

True or False: Stem cells have no specialized function and are coerced to specialize into different types of cells.

Answer 27

True