Ch. 2 - Cells

chromatid

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

Macrophage

phagocytic cell derived from a monocyte; may be fixed or wandering

Prometaphase

The second stage of mitosis, during which the nuclear envelope fragments and the spindle microtubules attach to the kinetochores of the sister chromatids.

Mitochondrial Theory

The theory that aging is caused by the decay of mitochondria, tiny cellular bodies that supply energy for function, growth, and repair.

telomerase

catalyzes the lengthening of telomeres in germ cells

fat cell

cell that stores nutrients

oocyte and sperm cells

cells of reproduction

macrophage / phagocylic cell

cells that fight disease

nerve cells (neurons)

cells that gather information and control body functions

Skeletal and smooth muscle cells

cells that move organs and body parts

Anaphase

centromeres split; identical sets of chromosomes move to opposite poles of the cell

Genetic Theory

cessation of mitosis and cell aging are programmed into genes

Nucleosome

chromatin beads that makes up double stranded DNA wrapped twice around a core of eight proteins called histones

Prophase

first and longest phase of mitosis, during which the chromosomes become visible and the centrioles separate and take up positions on the opposite sides of the nucleus

glycosomes

granules of stored glycogen that provide glucose during periods of muscle cell activity

Histone

help organize the coiling and folding of DNA

Cell theory

idea that all living things are composed of cells, cells are the basic units of structure and function in living things, and new cells are produced from existing cells

Endocytosis

materials move into a cell in a vesicle formed from the plasma membrane

Endoplasmic Reticulum

network of membranes in the form of flattened sacs or tubules

Karyokineses

nuclear division

Enzyme

protein that acts as a biological catalyst

Cis/Trans face

receiving and shipping departments of the golgi apparatus

S Phase

replication of DNA and centrosomes

Nuclear envelope

separates the nucleus from the cytoplasm

Cisternae

small, flattened membranous sacs with bulging edges that resemble a stack of pita bread

endosymbiotic theory

states that mitochondria and chloroplasts in today's eukaryotic cells were once separate prokaryotic microbes

Receptors

* serve as cellular recognition sites * each type of receptor recognizes and binds a specific type of molecule

Fibroblast

*A large, flat cell that secretes most of the extracellular matrix of areolar and dense connective tissues. *Connect body parts

pinocytosis (bulk-phase endocytosis)

"cell drinking" - most body cells have form of endocytosis in which tiny droplets of extracellular fluid are taken into the cell

Phagocytosis

"cell eating" - form of endocytosis in which the cell engulfs large solid particles such as worn-out cells, whole bacteria, or viruses

Cytoplasm

* All of the cellular contents between the plasma membrane and the nucleus. * Has two components: cytosol and organelles

G1 phase

* Cell duplicates most of its organelles and cytosolic components * Replication of chromosomes begins

peroxisomes

* Contain oxidase enzymes that detoxify alcohol, hydrogen peroxide, and other harmful chemicals * found in liver or where lipids are stored, broken down, or synthesized

Rough ER

* Continuous with the nuclear membrane and usually is folded into a series of flattened sacs. * Outer surface is studded with ribosomes *pancreas

Smooth ER

* Extends from the rough ER to form a network of membrane tubules * No ribosomes *liver cells, cells of ovaries & testes

facilitated diffusion

* Movement of specific molecules across cell membranes through protein channels with the assistance of transmembrane proteins functioning as carriers * Allows some molecules that are too large to fit through the protein pores and others insoluble in lipids to pass through the plasma membrane

Mitosis

* Nuclear division * two sets of chromosomes into separate nuclei

Interphase

* Period of the cell cycle between cell divisions * Cell replicates its DNA *3 phases: G1 phase, S phase, & G2 phase

Osmosis

* diffusion of water across a selectively permeable membrane from an area of higher water concentration to an area of lower water concentration. * Osmosis moves water b/w various compartments of the body

Integral proteins

* extend into or through the lipid bilayer and are firmly embedded in it * most integral proteins are transmembrane proteins (span the entire lipid bilayer and protrude into both the cytosol and extracellular fluid)

Lysosomes

* membrane-enclosed vesicles that form from the Golgi Complex * Their abundance is greatest in phagocytes, such as macrophages, but almost all cells contain some lysosomes.

fluid mosaic model

* model that describes the arrangement and movement of the molecules that make up a cell membrane * resembles a continually moving sea of lipids that contains a "mosaic" of many different proteins.

Mitochondria

* produce ATP - Adenosine Triphosphate * found in fat and muscle cells

Nucleolus

Found inside the nucleus and produces ribosomes

Exocytosis

Releases materials from a cell

Nucleoside

base + sugar

Golgi Apparatus

*An organelle in the cytoplasm of cells consisting of four to six cisternae that functions in processing, sorting, packaging, and delivering proteins and lipids to the plasma membrane, lysosomes, and secretory vesicles. *Each cisternae is made up of a flattened disk that carries enzymes meant to help or modify the protein cargo that travels through them. *The golgi apparatus has two faces. The CIS face points towards the ER and is the receiving side, and the trans face which points towards the membrane.

Ribosome

*site of protein synthesis *found free in cytoplasm or rough ER *not technically organelles because they are not membrane-enclosed, instead they are macromolecules made of both RNA and proteins. *eukaryotic cells that specialize in producing proteins have particularly large numbers of ribosomes.

Cell function

*structure *support *facilitate growth through mitosis *allow passive/active transport *produce energy *create metabolic reactions and aid in reproduction

active transport

Energy-requiring process that moves material across a cell membrane typically from an area of lower concentration to an area of higher concentration

Nucleotide

A building block of DNA, consisting of a five-carbon sugar covalently bonded to a nitrogenous base and a phosphate group.

Plasma membrane

A flexible yet sturdy barrier that surrounds and contains the cytoplasm of a cell.

Free Radical theory

A microbiological theory of aging that states that people age because inside their cells normal metabolism produces unstable oxygen molecules known as free radicals. These molecules ricochet around inside cells, damaging DNA and other cellular structures.

centrosomes

A pair of centrioles plus pericentriolar matrix

selective permeability

A property of a plasma membrane that allows some substances to cross more easily than others.

Vesicle

A small bladder or sac containing liquid

Organelle

A tiny cell structure that carries out a specific function within the cell (ex. ribosomes, endoplasmic reticulum, Golgi complex, lysosomes, peroxisomes, and mitochondria.

Glycocalyx

An extensive sugary coat that acts like a "molecular signature" that enables cells to recognize one another, adhere to one another in some tissues, and protects cells from being digested by enzymes in extracellular fluid.

Protein

An organic compound that is made of one or more chains of amino acids

Centromeres

Area where the chromatids of a chromosome are attached

Cellular Diversity

Cellular diversity is important when building complex organisms such as the human body because diversity, or variation allows the cells to be better adapted.

Metaphase

Centromeres of chromatid pairs line up at metaphase plate

Telomeres

DNA at the tips of chromosomes

Why do various types of cells have varying abundance of organelles?

Different types of cells have different amounts of some organelles. For instance, cells that use a lot of energy tend to contain large numbers of mitochondria

cytoplasmic inclusions

Impermanent structures in the cytoplasm such as lipid droplets and glycogen containing glycosomes.

Cytosol

Intracellular fluid - fluid portion of the cytoplasm that surrounds organelles

phagolysosome

Intracellular vesicle formed by fusion of a phagosome with a lysosome, in which the phagocytosed material is broken down by degradative lysosomal enzymes.

Nucleus

Large organelle that houses most of a cell's DNA

Cytoskeleton

Made up of microfilaments, intermediate filaments, and microtubules.

Diffusion

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

Peripheral proteins

Not as firmly embedded into the membrane and are attached to membrane lipids or integral proteins at the inner or outer surface of the membrane.

Telophase

Nuclear envelopes and nucleoli reappear; chromosomes resume chromatin form; mitotic spindle disappears

Coated pit

Parts of the cell membrane that have a hairlike coating necessary for endocytic functions. These portions of the cell membrane pinch off to form vesicles that aid in the intracellular transport of materials.

Coated Vesicle

Small membrane-enclosed sac that wears a distinctive layer of proteins on its cytosolic surface. It is formed by pinching-off of a protein-coated region of a cell membrane.

Lipid droplets

Storage of esterified forms of fatty acids as high energy storage molecules

Chromosones

Strands of DNA (deoxyribonucleic acid) molecules that carry genetic information.

receptor-mediated endocytosis

a highly selective type of endocytosis by which cells take up specific ligands (molecules that bind to specific receptors) ex. cholesterol

phospholipid bilayer

a two-layered arrangement of phosphate and lipid molecules that form a cell membrane, the hydrophobic lipid ends facing inward and the hydrophilic phosphate ends facing outward.