Chapter 3- The Cell

Eukaryote

A cell that contains a nucleus and membrane bound organelles

Prokaryote

A unicellular organism that lacks a nucleus and membrane bound organelles

Organelle

specialized structure that performs important cellular functions within a eukaryotic cell

Diploid

An organism or cell having 2 complete sets of chromosomes

Haploid

An organism or cell having only one complete set of chromosomes.

Osmosis

Diffusion of water through a selectively permeable membrane

Diffusion

Movement of molecules from an area of higher concentration to an area of lower concentration.

Hydrophobic

Having an aversion to water; tending to coalesce and form droplets in water.

Hydrophilic

Having an affinity for water.

Hypertonic

Having a higher concentration of solute than another solution.

Hypotonic

Having a lower concentration of solute than another solution

Isotonic

Having the same solute concentration as another solution.

Lyse

Cell bursting.

Plasma membrane

A selectively-permeable phospholipid bilayer forming the boundary of the cells

Nucleus

Control center of the cell; contains DNA; two membranes

Chromatin

Clusters of DNA, RNA, and proteins in the nucleus of a cell

Euchromatin

The less condensed form of eukaryotic chromatin that is available for transcription.

Heterochromatin

Eukaryotic chromatin that remains highly compacted during interphase and is generally not transcribed.

Nucleoli

dense masses of RNA and protein that manufacture ribosomes, several of these are located in the nucleus.

Rough endoplasmic reticulum

System of internal membranes within the cytoplasm. Membranes are rough due to the presence of ribosomes. functions in transport of substances such as proteins within the cytoplasm

Smooth endoplasmic reticulum

An endomembrane system where lipids are synthesized, calcium levels are regulated, and toxic substances are broken down.

Golgi apparatus (complex)

Packages and sends proteins; Assists in the transport, but is not the actual transport network

Exocytosis

Process by which a cell releases large amounts of material

Centrioles

Cell organelle that aids in cell division in animal cells only

Mitochondria

An organelle found in large numbers in most cells, in which the biochemical processes of respiration and energy production occur.

Ribosomes

site of protein synthesis

Vesicles

small membrane sacs that specialize in moving products into, out of, and within a cell

Lysosomes

A vesicle containing digestive enzymes

Cytoplasm

A jellylike fluid inside the cell in which the organelles are suspended

Matrix

Innermost compartment of the mitochondrion

Kreb's cycle

second stage of cellular respiration, in which pyruvic acid is broken down into carbon dioxide in a series of energy-extracting reactions

Where does the Kreb's cycle occur?

matrix of mitochondria

Electron Transport Chain (ETC)

A sequence of electron carrier molecules (membrane proteins) that shuttle electrons during the redox reactions that release energy used to make ATP.

Where does the ETC occur?

inner membrane of mitochondria

Chemiosmosis

A process for synthesizing ATP using the energy of an electrochemical gradient and the ATP synthase enzyme.

Interphase

period of the cell cycle between cell divisions; cell grows and carries on with normal business

G1 phase

The first gap, or growth phase, of the cell cycle, consisting of the portion of interphase before DNA synthesis begins.

S1 phase

phase of chromosomal replication and DNA synthesis during interphase

G2 phase

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

G0 phase

A nondividing state occupied by cells that have left the cell cycle, sometimes reversibly.

Apoptosis

process of programmed cell death

Mitosis

part of eukaryotic cell division during which the cell nucleus divides

Prophase

Chromosomes become visable, nuclear envelop dissolves, spindle forms

Metaphase

second phase of mitosis, during which the chromosomes line up across the center of the cell

Anaphase

the third phase of mitosis, during which the chromosome pairs separate and move toward opposite poles

Telophase

the final phase of cell division, between anaphase and interphase, in which the chromatids or chromosomes move to opposite ends of the cell and two nuclei are formed.

Cytokinesis

Division of the cytoplasm during cell division

Chromosome

A threadlike, gene-carrying structure found in the nucleus. Each chromosome consists of one very long DNA molecule and associated proteins.

Chromatid

one of two identical "sister" parts of a duplicated chromosome

Homologous chromosomes

Chromosomes that have the same sequence of genes and the same structure