A&P - Cells Notes

Plasma membrane (cell membrane)

seperates cytoplasm from the extracellular fluid

phospholipid bilayer

hydrophilic heads- face outwards on both sides, toward watery environments, hydrophobic acid-fatty tails- inside membrane, barrier to ions and water soluable compounds

integral proteins

within membrane

peripheral proteins

bound to inner or outer surface of membrane

receptor proteins

binds and responds to ligands (ions, hormones)

carrier proteins

transport specific solutes through membrane

channels

regulate water flow and solutes passingthrough membrane

gated Chanels…

Open or close to regulate passage of substances

cytoplasm

all materials inside the cell, outside the nucleus

cytosol (intracellular fluid)

contains dissolved materials (nutrients, ions, proteins and waste products)

organelles

structures with specific functions

nonmembranous organelles

no membrane, direct contact with cytosol, include cytoskeleton, centrioles, ribosomes, proteasomes, microvilli, cilia, and flagella

membraneous organelles

isolated from cytosol by a plasma membrane, ER, golgi apparatus, lysosomes, peroxisomes, nd mitochondria

cytoskeleton

structural proteins for strength and shape.

microfilaments

thin filaments composed of the protein actin

intermediate filaments

mid-sized between microfilaments and microtubules (durable, strengthen the cell and maintain shape)

microtubules

large hollow tubes of tubulin proteins

microvilli

increase surface area for absorption, attach to cytoskeleton

centrioles

form spindle apparatus during cell division

centrosome

cytoplasm next to the nucleus that surrounds centrioles

cilia

slender extensions of plasma membrane

motile cilia

found on cells lining the respiratory and reproductive tracks

flagellum

a whip like extensionof cell membrane

ribosomes

synthesize proteins, contain rRNA

free ribosomes in a

cytoplasm

fixed ribosomes are

attached to ER

endoplasmic reticulum (ER)

contains storage chambers known as cisternae, synthesis of proteins, carbohydrates and lipids

smooth ER

no attached ribosomes, synthesizes, phospholipids and cholesterol and steriod hormones

rough ER

surface covered with ribosomes, encloses products in transport vesicles for delivery to Golgi apparatus

golgi apparatus (golgi complex)

vesicles enter forming face and exit maturing face, modifies and packages secretions

lysosomes

powerful enzyme-containing vesicles produced by golgi apparatus, destroy bacteria, break down molecules, nd recycle damage organelles

peroxisomes

small, enzyme containing vesicles

mitochondria

inner membrane has numerous folds (Cristae), take chemical energy from food (glucose) and produce ATP

cristae

surround fluid contents (matrix)

Glycolysis

glucose to pyruvic acid (in cystol), mitochondria absorb pyruvate molecules

citric acid cycle

occurs in mitochondrial matrix, breaks down pyruvate

electron transport chain

inner mitochondrial membrane

aerobic metabolism (cellular respiration)

mitochondria use oxygen to break down food and produce ATP, produces 95 percent of ATP needed to keep cell alive

nucleus

largest organelle, the cell’s control center

nuclear envelope

double membrane around the nucleus

nuclear pores

communication passages in nuclear envelope

nuclear matrix inside…

the nucleoplasm

nucleoli

nuclear organelles, synthesize rRNA and assemble ribosomal subunits

nucleosome

DNA coiled around histones

loosely coiled into ____ in non dividing cells

chromatin

tightly coiled ____ form before division

chromosomes

protein synthesis

assembling of functional polypeptides in the cytoplasm

gene activation

uncoiling DNA and temporarily removing histones

transcription

synthesis of RNA and DNA template, all RNA, including messenger RNA, is formed through transcription of data

coding strand of DNA

specifies the sequence of amino acids and polypeptides

template strand

used for mRNA production

translation

after leaving nucleus, mRNA binds to ribosomal subunits in cytoplasm, amino acids are delivered by transfer RNA (tRNA)

tRNA anticodon…

binds to a complementary mRNA codon

Permeability

determines what moves in an out of the cells

impermeable

nothing in or out

freely permeable

anything pass

selectively permeable

restricts movement

plasma membrane is

slectively permeable

diffusion

movement from area of high concentration to low concentration, ions and molecules are constantly in motion

concentration gradient

difference between high and low concentrations of a substance

molecules move randomly in a process called

brownian motion

passive transport

movement down a concentration gradient

active transport

movement against a concentration gradiant

permeable

simple, small non polar solutes, oxygen, carbon dioxide and steroid hormones

impermeable

channels, large, polar solutes, carbohydrates, proteins, charaged ions

simple diffusion requires

no energy

facilitated diffusion requires

no energy

simple diffusion

direct movement of a solute across a semi-permeable membrane

osmosis

movement of water across a membrane due to imbalance in solute concentration

a cell in an isotonic solution

stays the same size and shape

a cell in a hypotonic solution

gains water and may rupture (hemolysis)

a cell in a hypertonic solution

loses water and shrinks (crenation)

faccilitated diffusion

movement of impermeable solutes using transport proteins

carrier protein

binds solutes and chaperones them across membrane

carrier mediated faccilitated diffusion

passive, molecule binds to receptive site on protein

active transport

move substrates against concentration gradiants, requires energy such as ATP

ion pumps

move ions

exchange pumps

move two ions in opposite directions at the same time

primary active transport

pumping solutes against a concentration gradiant using ATP

sodium potassium echange pumps

one ATP powers the movement of three sodium ions Na+ out and two potassium ions in (K+)

interphase

non dividing phase

dna replication - s phase

helicase unwind dna strands

dna polymerase

promotes bonding between nitrogenous bases in dna and complimentary dna nucleotides dissolved in the nucleoplasm, links the nucleotides by covalent bonds

mitosis

duplication of chromosomes in the nucleus