Unit 4 Honors Biology

Cell division

The continuity of life by the reproduction of cell by division

Genome

A cells genetic information

Chromosomes

DNA molecules packaged into structures

Chromatin

The entire complex of DNA and proteins that is the building material of chromosomes

Somatic cells

All body cells except reproductive cells

Gametes

Reproductive cells (sperm+egg cells)

Sister chromatids

Each duplicated chromosome consists of 2 of these (joined copies of the OG chromosome)

Centromere

A region made up of repetitive sequences in the chromosomal DNA where the sister chromatids are connected

Mitosis

The division o the genetic material in the nucleus

Cytokinesis

The division of the cytoplasm

Mitotic (M) phase

Part of the cell cycle that includes mitosis and cytokinesis

Interphase

90% of the cell cycle which includes gap 1, gap 2, and S phase

Gap 1

Growth phase

Gap 2

DNA synthesis

S phase

“Last check”

Prophase

Chromosomes coil up, spindle fibers form , and nuclear membrane breaks down

Prometaphase

Transitional phase in which the nuclear envelope breaks down

Metaphase

(Middle), chromosomes line up in the middle of the cell, spindle fibers attach to each chromosome

Anaphase

Centromeres divided, sister chromatids separate into individual chromosomes, chromosomes move to opposite ends of the cell

Telophase

(Two nuclei) chromosomes gather at opposite ends of the cell, two new nuclear membranes form, chromosomes uncoil, spindle fibers dissolve

Mitotic spindle

A complex of microtubules and proteins that segregate chromosomes

Centromere

The connector of the sisters chromatids which make the chromosome

Kinectochore

A coupling device that attaches the motor of the spindle (to pull apart)

Metaphase plate

The centromeres of the duplicated chromosomes are on an invisible plane between the 2 spindle poles

Cleavage

In animal cells, the process of cytokinesis

Cleavage furrow

A shallow groove in the cell surface near the old metaphase plate (breaks of cytoplasm)

Cell plate

During cytokinesis, plant cells form a cell plate to separate the cytoplasm

Binary fission

Asexual mitosis in single cell eukaryotes

Cell cycle control system

A cyclically operating set of molecules in he cell cycle hat both triggers and coordinates key events in the cell cycle

Checkpoint

In the cell cycle is a control point where stop and go- ahead signals can regulate the cycle

G0 phase

If a cell does not receive a go-ahead signal at that point, it may exit the cycle, witching into a non dividing state

Cyclin

Regulatory protein

Cyclin dependent kinases

A family of enzymes crucial for controlling the cell cycle

MPF

A crucial protein complex that triggers both mitosis and meiosis

Growth factor

A protein released by certain cells that stimulate other cells to divide

Density-dependent inhibition

A phenomenon in which crowded cells stop dividing

Anchorage dependence

When most animal cells divide, they must be attached to something

Transformation

When cells in culture acquire the ability to divide indefinitely

Benign tumor

Tumors that don’t cause serious problems and an be removed by surgery

Malignant tumor

Cells whose genetic and cellular changes enable them to spread to new tissue and impair the functions of organs

Enzyme

A macromolecule that acts as a catalyst

Catalyst

Chemical agent that speeds up a reaction without being consumed by that reaction

Activation energy or Ea

Can create a barrier that determines the rate of the reaction because the reactants must absorb enough energy before the reaction can occur

Ae or Ea

The amount of energy needed to push the reactants to the top of an energy barrier (uphill), so the “downhill” reaction can occur

Catalysis

The process by which a catalyst selectively speeds up a reaction

Enzymes are…

Proteins

Substrate

The reactant an enzyme acts on is referred

Enzyme-substrate complex

The enzyme binds to its substrate forming ESC

Active site

Typically a pocket or groove on the surface of the Blume were catalysis occurs

Induced fit

Clasping handshake- bringing chemical groups o the active site into positions that enhance their ability to catalyze the chemical reaction

What does high temperature do

Destroys proteins and kills cells

What does pH do

Alters the charges of amino acids preventing affective binding

Allosteric regulation

Proteins function affected by binding to a regulatory molecule

Activation regulation

Binding to increase activity/turning and enzyme “on”

Inhibition regulation

Binding to decease activity/ turning an enzyme “off”

Cofactors

Non-protein chemical compounds or metallic ions that help enzymes function properly

Coenzyme

If the cofactor i an organic molecule

Competitive inhibitors

Reduce the productivity of enzymes by blocking substrates from entering active sites

Noncompetitive inhibitors

Do not directly compete with the substrate to bin to the enzyme at the active site

Feedback inhibition

Common mode of metabolic pathway is halted by the inhibitory binding of its end product to and enzyme that acts early in the pathway (regulates by having the pathways final product inhibit an early; rate-limiting enzyme, preventing overproduction and conserving resources