APBio Unit 4 Cellular Communication, Cell Cycle, Homeostasis

Homeostasis

The body's ability to maintain relatively stable internal conditions even though the outside world is continuously changing.

Stimulus

causes change

Receptors

monitors changes then sends information to the control center

Set Point

the level that is to be maintained

Effector

causes a response to change conditions

Response

result of the stimulus

Negative Feedback

-depresses or stops the conditions to return toward set point

-Most conditions in the body

Positive Feedback

-enhances or continues the response away from set point

-Examples: childbirth, blood clotting

Ectotherm

internal temperature conforms to ambient temperature.

Endotherm

able to maintain body temperature at a different level than the environment

Standard Metabolic Rate

the metabolic rate of an ectotherm at rest at a specific temperature

Basal Metabolic Rate

minimum metabolic rate of an endotherm at rest.

Osmoconformers

their osmolarity equilibrates with that of seawater. results in energetic savings.

Osmoregulators

have tissue fluid that is different from the external environment. They must actively regulate the osmolarity of their extracellular fluids. Requires energy

Digestive System

Composed of the alimentary canal and accessory structures. Mouth, esophagus, stomach, small intestine (duodenum, jejunum, and ileum), large intestine (colon), and anus, Breaks down food into absorbable units that enter the blood for distribution to body cells.

Circulatory System

(aka cardiovascular system) This system works as the transportation highway for the body. It consists of the heart, blood, and blood vessels. It transports substances such as oxygen, carbon dioxide, and nutrients in the body.

Respiratory System

A system of organs, functioning in the process of gas exchange between the body and the environment, consisting especially of the nose, nasal passages, nasopharynx, larynx, trachea, bronchi, and lungs.

Lymphatic / immune System

Composed of red bone marrow, thymus, spleen, lymph nodes, lymphatic vessels; picks up fluid leaked from blood vessels and returns it to the blood; Involved with immunity; Without the system, the body would swell as fluid becomes trapped in your tissues. Protects the body from foreign substances and pathogenic organisms by producing the immune response

Excretory System

Group of organs that purify the body by the elimination of waste matter

Endocrine System

The body's "slow" chemical communication system; The glands and parts of glands that produce endocrine secretions, help to integrate and control bodily metabolic activity, and include especially the pituitary, thyroid, parathyroid, adrenals, islets of Langerhans, ovaries, and testes.

Reproductive System

organ system responsible for producing, storing, and delivering gametes

Nervous System

the body's speedy, electrochemical communication network, consisting of all the nerve cells of the peripheral and central nervous systems.

Integumentary system

Consists of the skin, mucous membranes, hair, and nail, largest organ of the human body.

Skeletal System

Creates framework of the body, protects internal organs, produces blood cells, acts as levers for muscles. Ex: bones and cartilage, provide for organ attachment.

Muscular System

Consists of skeletal muscles, tendons that connect muscles to bones, and ligaments that attach bones together to form joint, enables movement of the body and internal organs

ligand

A molecule that binds specifically to a receptor site of another molecule.

Cell Cycle

The regular sequence of growth and division that cells undergo

signal transduction pathway

The process by which a signal on a cell's surface is converted into a specific cellular response.

Interphase

Cell grows, performs its normal functions, and prepares for division; consists of G1, S, and G2 phases

local regulators

These regulators influence cells in the vicinity of them.

G1 Phase

stage of interphase in which cell grows and performs its normal functions

hormones

Chemical messengers, mostly those manufactured by the endocrine glands, that are produced in one tissue and affect another

G2 Phase

The second growth phase of the cell cycle, consisting of the portion of interphase after DNA synthesis occurs.

protein kinases

The enzyme that transfers phosphate groups from ATP to protein.

S Phase

The synthesis phase of the cell cycle; the portion of interphase during which DNA is replicated.

second messengers

Small, non-protein water soluble molecules or ions that send messages throughout the cells by diffusion.

Checkpoint

A critical control point in the cell cycle where stop and go-ahead signals can regulate the cycle.

Mitosis

A nuclear division resulting in the production of two somatic cells having the same genetic complement as the original cell.

hydrophobic ligands

signaling molecules that can cross plasma membrane and bind to intracellular receptors in cytoplasm

Cytokinesis

Process by which the cell cytoplasm divides

hydrophilic ligands

signaling molecules that cannot cross plasma membrane and bind to membrane receptors

Cancer

A disease in which some body cells grow and divide uncontrollably, damaging the parts of the body around them.

receptor proteins

proteins in the plasma membrane that are sensitive to the presence of specific extracellular molecules called ligands

Tumor Suppressor Protein

have a damping or repressive effect on the regulation of the cell cycle

quorum sensing

The ability of bacteria to sense the presence of other bacteria via secreted chemical signals.

Prophase

Chromatin condenses,

chromosomes become visable, nuclear envelop dissolves, spindle forms

autocrine signaling

the target cell is also the secreting cell

Prometaphase

The second stage of mitosis, in which discrete chromosomes consisting of identical sister chromatids appear, the spindle microtubules attach to the kinetochores of the chromosomes

paracrine signaling

the target cells lie near the secreting cells

Metaphase

Centromeres of duplicated chromosomes are aligned at plate. Fully formed spindle attach to the sister chromatids from opposite poles

Anaphase

Phase of mitosis in which the chromosomes separate and move to opposite ends of the cell

endocrine signaling

secreted molecules diffuse into the bloodstream and trigger responses in target cells anywhere in the body

Telophase

Final phase of mitosis during which chromosomes uncoil, a nuclear envelope returns around the chromatin, and a nucleolus becomes visible in each daughter cell

Sister Chromatids

Replicated forms of a chromosome joined together by the centromere and eventually separated during mitosis or meiosis II.

Spindle Fibers

Made of microtubules that connect centrioles to kinetochores of chromosomes and that separate sister (mitosis) or homologous (meiosis) chromosomes during cell division

Homologous Chromosome

Chromosomes that are similar in size, shape, and genetic content

Centromere

Region of a chromosome where the two sister chromatids attach

Cdk

A key protein in the control of the cell cycle; combines with cyclin.

Cyclin

A cellular protein that occurs in a cyclically fluctuating concentration and that plays an important role in regulating the cell cycle. Will bind to Cdk forming MPF

MPF

A cyclin-Cdk complex that triggers the cell's passage past the G2 checkpoint into mitosis?

Diploid

A cell that contains two complete sets of chromosomes, (homologous chromosomes) one from each parent.

Centrioles

a minute cylindrical organelle near the nucleus in animal cells, occurring in pairs and involved in the development of spindle fibers in cell division.

Chromatin

DNA and protein that makes up chromosomes