The Cell Cycle (Chapter 4)

Simple Diffusion

- net movement of dissolved particles down their concentration gradient without energy (ATP)`

Haploid

1 Single set of unpaired chromosomes

Cells Divide When

1. They grow large enough to have enough cytoplasm to distribute to their 2 daughter cells. 2. They have replicated their DNA, so they give each daughter cell a duplicate of their genes. 3. They receive an adequate supply of nutrients. 4. They are stimulated by growth factors, chemical signals secreted by blood platelets, kidney cells, & the other sources. 5. Neighboring cells die, opening up space in a tissue to be occupied by new cells.

Diploid

2 complete sets of chromatids, 1 from each parent

Homologous Chromosomes

2 sister Chromosome Pairs have the same exact structure

S Phase

A cells commitment to cell division is most likely to be entry into which phase of the cell cycle?

Isotonic Solution

A solution in which the concentration of solutes is essentially equal to that of the cell which resides in the solution

Vasodilation

Blood moves closer to skin - Heat loss by heat flowing down its concentration gradient into the air. (Air is usually cooler than your normal body temp)

Cancer Cells

Cells that divide uncontrollably

G0 (G-Zero) Phase

Cells that leave the cell cycle during G1 to divide for days, years, or the rest of one's life to mature neurons, skeletal muscle cells.

Chemotherapy targets rapidly dividing cells, which are located in skin cells and in the digestive tract.

Chemotherapy often results in naseau, diarrhea, and hair loss. Why is that?

Mitosis

Development of an individual, composed of some 50 trillion cells, from a 1-celled fertilized egg. - Growth of all tissues & organs after birth - Replacement of cells that die - Repairs damaged tissue

Cytokinesis

Division of the Cytoplasm into 2 cells - Achieved by the motor protein myosin pulling on microfilaments of actin in the terminal Web of the cytoskeleton. - Creates a crease called cleavage furrow around the equator of the cell, cell pinches in 2, Interphase has now begun.

Telophase

During which phase of mitosis does the nuclear membrane Reform?

Prophase

During which phase of mitosis does the nuclear membrane disintegrate?

Active Transport

Energy-requiring process that moves material across a cell membrane against a concentration difference`

Telophase

Final Stage of Mitosis - Telo means end - CHROMOSOMES cluster at each side of the cell. - Rough ER produces a new nuclear envelope around each cluster & chromosomes begin to uncoil & return to thinly dispersed chromatin form. - Mitotic Spindle breaks up & vanishes - Each new nucleus forms nucleoli, indicating it has already begun making RNA & is preparing for protein synthesis.

G1 - Phase 1

First Gap Phase, An interval between feel division and Dna Replication - A cell synthesizes proteins, grows, & carries out its preordained tasks for the body. - Accumulate the materials needed to replicate their DNA in the next phase. -LONGEST PHASE

Phrophase

First stage of Mitosis - Longest Stage - Pro means first - Chromosomes shorten & thicken - 46 Chromosomes each with 2 chromatids & 1 molecule of DNA per chromatid. - DNA breaks into visible chromosones and nuclear membrane breaks down. -Centrioles move to oppposite ends of the cell. Mitotic spindle (made of tubular proteins) begins to form. -CHROMATIN organizes into CHROMOSOMES

Neurons can't divide, unlike liver cells, neurons need to last your entire life, if they are damaged they are gone.

If you damage your liver, new liver cells can be produced to replace 75 % of the liver. However, if you sustain brain damage, your body does not produce new brain cells (Neurons) Why is this?

G1: 1 set - 46 chromosomes S: 2 sets - 92 chromosomes G2: 2 sets - 92 chromosomes M: 1 Set - 46 chromosomes

In each phase in the cell cycle how many sets of DNA are present in each cell at the end of each phase?

Gradient

Is a difference in chemical concentration between 1 point to another. Water Flows down the concentration gradient from high to low

Hereditary

Is the transmission of genetic characteristics from parent to offspring.

M - Phase 4

Mitotic Phase - A cell replicates its nucleus and then pinches in 2 to form 2 new daughter cells

Facilitated Diffusion

Movement of specific molecules across cell membranes through protein channels`

Tumor Suppresor Gene = BRCA1

Normal tumor suppressor genes inhibits excess cell division and slows down cell growth.

Apoptosis

Programmed cell death

Neoplasia

Rapidly Dividing Cells

G2 - Phase 3

Second Gap Phase: Relatively brief interval. - A cell exhibits further growth, makes more organelles finishes replicating its centrioles, & Synthesizes enzymes that control cell division. - Checks fidelity of DNA replication & Repairs errors.

Metaphase

Second Stage of Mitosis - Meta means Next - The chromosomes are aligned on the cell equator awaiting signal to split into 2 - Form Mitotic Spindle - Long microtubules reach out from each centriole to the chromosomes

Oncogene

Stimulates the cell cycle to excessive cell division when activated, Speeds up cell growth.

S - Phase 2

Sythesis Phase: A cell makes a duplicate copy of its centrioles & all of its nuclear DNA.

Chemotherapy

Targets rapidly dividing cells -Side Effects: Naseau, Diarrhea, Hair loss. - Is a toxin that targets cancer cells - Targets cells that are turning over rapidly & dividing, which are hair cells & digestive cells.

Contact Inhibition

The cessation of Cell Division in response to contact with other cells.

Hypotonic Solution

The concentration of solutes is greater inside the cell than outside it. The water will move into the cell.

Hypertonic Solution

The concentration of solutes is greater outside the cell than inside it.

Interphase

The first 3 Phases of the Cell cycle (G1, S, G2)

Tonicity

The measure of the effective osmotic pressure gradient, as defined by the water potential of 2 solutions separated by a semi-permeable membrane.

Osmosis

The spontaneous net movement of solvent molecules through a semi-permeable membrane into a region of higher solute concentration in the direction that tends to equalize the solute concentrations on 2 sides.

Anaphase

Third Stage of Mitosis - Ana means apart - Begins with activation with an enzyme that cleaves the 2 sister CHROMATIDS from each other at centromere. - 1 Daughter chromosome migrates to each pole of the cell, with its centromere leading the way & arms trailing behind. - Migration is achieved

Hydrophobic

Water hating

Hydrophilic

Water loving

G1 - When a cell grows cell size increases M - Number of cells increase

What 2 phases can an organism actually grow in the cell cycle?

Each 1 cell will start with 6 chromosomes then divide into 2 so that each new cell will still have 6 chromosomes in it.

What is a Diploid number of 6 in a cell?

2 Identical Daughter Cells

What is the result of mitosis?

Hair cells & digestive Cells

Which cells have rapid cell growth and division?

G1, because its the longest phase of the cell cycle.

Which phase are most cells of the body going to be in & Why?

G1 Phase

Which phase does a cell carry out normal functions in?

Mitosis

Which phase of the cell cycle is the shortest?

The cells that are in your eyebrow, those skin cells are in the G0 phase, where they don't grow or create new cells, they are stuck in their cells for the rest of their lives. - Happens in the G1 Phase

Why can't you braid your eyebrows? Where does this happen in the Cell Cycle?

Their cells didn't follow the normal limitations of Division. DNA is damaged before it is able to make a replication of itself, then it replicates damaged cells. - Or a decrease in Interphase, more cells to form - Change in Mitosis, More cells to form.

Why might someone have formed skin cancer?

Active vs. Passive Transport

passive = doesnt use energy, more type