bio 120 final

Five Fundamental Characterisitics

cells, replication, evolution, information, and energy

theory

an explanation for a very general class of phenomena or observations and is supported by a wide body of evidence

Scientific theory

is an explanation of some aspect of the natural world that has been substantiated through repeated experiments

Three Theories

the cell theory, the theory of evolution by natural selection, and the chromosome theory of inheritance

Robert Hooke and Anton van Leeuwenhoek

first to observe cells

cell

a highly organized compartment bounded by a plasma membrane

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

phylogeny

Evolutionary history of a species

plasma membrane

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

phospholipids

A molecule that is a constituent of the inner bilayer of biological membranes, having a polar, hydrophilic head and a nonpolar, hydrophobic tail.

lipids

carbon containing compounds found in organisms, largely non polar and hydrophobic, fats are lipids

hydrocarbons

Compounds composed of only carbon and hydrogen

isoprenoid

hydrocarbon chain that functions as pigments, scents, vitamins

fatty acid

a hydrocarbon chain bonded to a carboxyl functional group

Saturated hydrocarbon chains

Consist of only single bonds between the carbons

unsaturated hydrocarbon chains

have at least one double bond

three most important types of lipids found in cells

steroids, fats, and phospholipids

phospholipids

consist of a glycerol linked to a phosphate group bonded to a charge or polar molecule

steroids

are a family of lipids distinguished by a bulky, four-ring structure

hydrophobic interactions

become stronger as saturated hydrocarbon tails increase in length

passive transport

occurs when substances diffuse across a membrane in the absence of an outside energy source

osmosis

diffusion of water

hypertonic

when comparing two solutions, the solution with the greater concentration of solutes

hypotonic

Having a lower concentration of solute than another solution

isotonic

when the concentration of two solutions is the same

fluid-mosaic model

model that describes the arrangement and movement of the molecules that make up a cell membrane

selective permeability

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

ion channels

A transmembrane protein channel that allows a specific ion to diffuse across the membrane down its concentration or electrochemical gradient.

channel proteins

proteins that provide passageways through the membrane for certain hydrophilic (water-soluble) substances such as polar and charged molecules

aquaporins

water channel proteins

gated channels

A protein channel in a cell membrane that opens or closes in response to a particular stimulus.

facilitated diffusion

Movement of specific molecules across cell membranes through protein channels

carrier proteins

a protein that transports substances across a cell membrane

morphology

study of form

eukaryotes

have a membrane-bound nucleus

prokaryotes

lack a membrane bound nucleus

bacterial cells

have a plasma membrane that consists of a phospholipid bilayer, has proteins that regulate what enters and exits the cell, and creates a distinct internal environment

cytoplasm

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

prokaryotic cells

contain a single, circular chromosome, composed of DNA and proteins, contain genes which code for polypeptides, tightly coiled to fit inside the cell

plasmids

small circular DNA molecules that replicate separately from the bacterial chromosome

nucleoid

A dense region of DNA in a prokaryotic cell.

cytoskeleton

A network of fibers that holds the cell together, helps the cell to keep its shape, and aids in movement

peptidoglycan

a structural polymer found in bacterial cell walls joined by beta-1-4 glycosidic linkages

eukaryotic chromosomes

are found inside a membrane-bound compartment called a nucleus

eukaryotic cells

are often much larger, feature a diverse and dynamic cytoskeleton, and contain extensive amounts of internal membrane

eukaryotic cells

have large surface-to-volume ratio

cytosol

Fluid portion of cytoplasm

nuclear envelope

layer of two membranes that surrounds the nucleus of a cell

nucelar lamina

lattice-like sheet of fibrous proteins

Nucleolus

Makes ribosomes

Heterochromatin

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

euchromatin

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

Ribosomes

Makes proteins

Rough Endoplasmic Reticulum

An endomembrane system covered with ribosomes where many proteins for transport are assembled.

Smooth Endoplasmic Reticulum

creates lipids or fat and is a reservoir for calcium ions

Golgi apparatus

stack of membranes in the cell that modifies, sorts, and packages proteins from the endoplasmic reticulum

cisternae

flattened stacked membrane folds

cis

surface closest to the nucleus

trans

surface is oriented toward the plasma membrane

lysosomes

recycling centers only found in animal cells

endomembrane system

lysosomes, golgi apparatus, and ER

vacuoles

Cell organelle found in plants and fungi that stores materials such as water, salts, proteins, and carbohydrates

peroxisomes

Contain oxidase enzymes that detoxify alcohol, hydrogen peroxide, and other harmful chemicals

Mitochondria

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

cristae

folds in the inner membrane of mitochondria

mitochondrial matric

the substance occupying the space enclosed by the inner membrane of a mitochondrion; it contains enzymes, filaments of DNA, granules, and inclusions of protein crystals, glycogen, and lipid.

chloroplasts

Capture energy from sunlight and use it to produce food for the cell

thylakoids

A flattened membrane sac inside the chloroplast, used to convert light energy to chemical energy.

grana

stacks of thylakoids

stroma

fluid portion of the chloroplast; outside of the thylakoids

endosymbiosis

A theorized process in which early eukaryotic cells were formed from simpler prokaryotes.

microfilaments

Long, thin fibers that function in the movement and support of the cell

microtubules

Spiral strands of protein molecules that form a tubelike structure

intermediate filaments

Threadlike proteins in the cell's cytoskeleton that are roughly twice as thick as microfilaments

actin filaments (microfilaments)

small fibrils that forms a bundles, sheets or networks in the cytoplasm; for structure, support for microvilli, contractility and movement

dimers

two monomers bonded together

microtubule organizing center

any structure that organizes microtubules

centrosome

A structure in animal cells containing centrioles from which the spindle fibers develop.

centrioles

Cell organelle that aids in cell division in animal cells only

nuclear localization signal (NLS)

A short amino acid sequence that marks a protein for delivery to the nucleus.

extracellular matrix

The substance in which animal tissue cells are embedded, consisting of protein and polysaccharides.

collagen

A glycoprotein in the extracellular matrix of animal cells that forms strong fibers, found extensively in connective tissue and bone; the most abundant protein in the animal kingdom.

proteoglycans

a glycoprotein consisting of a small core protein with many carbohydrate chains attached, found in the extracellular matrix of animal cells.

tissues

Groups of cells with a common structure and function.

laminins

ECM crosslinking proteins

integrins

membrane proteins; they transmit signals between the ECM and cytoskeleton

primary cell wall

In plants, a relatively thin and flexible layer first secreted by a young cell.

microfibrils

A threadlike component of the cell wall, composed of cellulose molecules

pectin

a soluble gelatinous polysaccharide that is present in ripe fruits and is extracted for use as a setting agent in jams and jellies.

multicellularity

The state of being composed of many cells that adhere to each other and do not all express the same genes with the result that some cells have specialized functions.

epithelia

layers of cells that cover internal or external surfaces

tight junction

A type of intercellular junction in animal cells that prevents the leakage of material between cells.

desmosomes

Anchoring junctions that prevent cells from being pulled apart

gap junctions

(communicating junctions) provide cytoplasmic channels between adjacent cells

symplast

In plants, the continuum of cytoplasm connected by plasmodesmata between cells.

apoplast

In plants, the continuum of cell walls plus the extracellular spaces.

ketose

carbonyl group in middle of carbon chain

aldose

carbonyl group at end of carbon chain

endocrine signaling

Specialized cells release hormone molecules into vessels of the circulatory system, by which they travel to target cells in other parts of the body.

surface proteins

A protein that resides primarily on the inner or outer surface of the phospholipid bilayer which constitutes the plasma membrane of the cell.