Bio Exam 1 (Microscope - Cells)

Transmission Electron Microscope (TEM)

provides detailed study of INTERNAL cell

slices

Scanning Electron Microscope (SEM)

provides detailed study of SURFACE of specimen

whole

Resolving Power

the ability of a lens to show two adjacent objects as discrete entities

Cell Fractionation

takes cells apart and separates the major organelles from one another

Homogenization

1st part of Cell Fractionation

using a blender to break up cells

Centrifugation

isolating cells into their compound parts

higher speeds & longer time = smaller organelles revealed

Supernatant

liquid left over from Centrifugation

Pellet

bottom part full of specific organelles

ALL CELLS

bounded by plasma membrane (selective)

contain semifluid material that suspends subcellular components - cytosol

chromosomes contain genes in form of DNA

contain ribosomes

Prokaryotic Cells

lack a true nucleus (DNA in nucleoid)

lack of membrane-bound organelles

Bacteria

Eukaryotic Cells

contain true nucleus & bounded by membranes nuclear envelope

posses membrane-bound organelles

a.) Plasma Membrane

permeability barrier to materials entering & leaving cell

determines the nature of cell-to-cell contact

specific physiological process (nerve impulse transmission)

posses receptors

a.) Phospholipid Bilayer

Ends of phosphate (hydrophilic)

hydrophobic portion of membrane is composed of lipids

b.) Nucleus

largest organelle

b.) Nuclear Envelope

2 membranes separated by space

b.) Pores

allow materials to enter or leave (ribosomes)

b.) Chromatin

fibrous complex formed from DNA in nucleus combined w/ proteins

long fine inter tangled threads

produce chromosomes when cell divides

b.) Nucleolus

spherical bodies, contains DNA, not enclosed by membrane, site of ribosome assembly

b.) Nucleoplasm

fluid within nucleus

suspended in it are particles, fibers and proteins

c.) Ribosomes

particle composed of RNA and protein

site of protein synthesis

FREE- located in cytosol (where protein functions)

BOUND/FIXED - attached to rough ER (li[id synthesis)

Endomembrane System

series of membranes that regulate protein intake and perform metabolic functions in the cell

d.) Endoplasmic Reticulum

network of membranes branching through cytoplasm

tubes and flattened sacs

make more than 1/2 total membrane in euk. cell

continuous with outer nuclear membrane

d.) Rough ER

covered w/ ribosomes on cytoplasmic side

site of protein synthesis for use in membrane or out of cell

d.) Smooth ER

no ribosomes, modifies proteins

lipid synthesis

metabolism of carbs, detox of drugs, calcium ions, forms transport

e.) Golgi Apparatus

receives the transport vesicles made in ER

flattened membranous sacs, stacked like saucers

packaging, sorting, secreting proteins

functions in exocytosis = out cell

Exocytosis

the process by which materials are exported from the cell and membrane incorporated into the plasma membrane

e.) cis face of golgi

located near ER & receives vesicles

CIS = comes in

e.) trans face of golgi

pinches off vesicles that move to other site

TRANS =

f.) Lysosome

membranous sac derived from golgi apparatus

contains hydrolitic (digestive) enzymes

site for breakdown of food/foreign objects

Phagocytosis

process by which a solid particle is taken into the cell by invagination of the cell membrane

Autophagy

Site of breakdown of damaged organelles

g.) Vacuole

sac surrounded membrane

1.) food- formed by endocytosis

2.) contractile - pumps excess water out of some cells

3.) central- filled with aqueous solution containing dissolved substances (found in most mature plants, few animal)

h.) Mitochondrion

powerhouse of cell

produces ATP (adenosine triphosphate)

2 membranes

1.) outer = smooth

2.) inner = many inward folds (cristae)

h.) Mitochondrion conti.

between membranes is intermembrane space

the region enclosed is matrix which contains DNA, ribosomes, enzymes

i.) Cytoskeleton

give cell structure

i.) Microfilaments

polymer of protein (actin)

aids in cell mobility and stabilizes cell shape

i) Intermediate filament

fibrous protein (keratin)

maintains position of organelles and cell shape

i.) Microtubules

polymer of protein (tublin)

long unbranched cylinders

aids in cell movement w/ celia and flagella

helps in cell division when chromosomes split

j.) Centrosomes

Microtubule organizing center, near nucleus

both animal and plant cells

j.) Centrioles

barrel-shaped

9 sets of triplets arranged in ring

aid in cell division

k.) Peroxisome

metabolic microbody bounded by single membrane

has enzyme that destroys toxic peroxides that form in cell

Converts to water

a.) Cell Wall

exterior to plasma membrane

semi rigid structure found outside the plasma membrane (nonliving) (not an organelle)

composed of cellulose embedded in a matrix of polysaccharides and proteins

provides support for cell & limits volume

a.) Primary Cell Wall

1st wall secreted by a young plant cell

a.) Secondary Cell Wall

2nd wall secreted by cell

located between the plasma membrane and the primary cell wall

a.)Middle Lamella

thin layer of sticky polysaccharides (pectins) located between two primary walls of adjacent cells

b.) Plastids

involved in the synthesis and storage of food and pigment formation

b.) Chloroplast

contains chlorophyll pigment (green color)

site of photosynthesis

composed of two membranes (smooth outer and inner membrane) (intermembrane space)

contains another membranous system, arranged into flattened sacs called internal to the inner membrane (stacked thylakoids call granum)

thylakoids surrounded by fluid called stroma ( contains enzymes, DNA, and ribosomes)

b.) Chromoplast

contains carotenoids (red,orange, yellow pigment)

may help to attract animals that assist in pollination

b.) Leucoplast

lacks pigment

storage depots for starch and oils

d.) Glyoxysome

specialized peroxisome found in fat storing tissues of plant seeds

contains enzymes that initiate the conversion of fatty acid to sugar

e.) Animal Cell- Extracellular matrix (ECM)

main ingredients- proteins, glycoproteins secreted by cells (collagen)

function - support, adhesion, movement, regulation

Intercellular Junctions

neighboring cells often adhere, interact, and communicate through special patches of direct physical contact

Tight Junctions

A specialized connection of two adjacent animal cell membranes such that the space usually lying between them is absent

ex.) stomach - stops flow of acid into surrounding organs/tissue

ANIMAL CELL

Desmosome

A structure that forms the site of adhesion between two cells, consisting of a dense plate of each adjacent cell separated by a thin layer of extracellular material

Ex.) some muscles and bladder (expanding)

ANIMAL CELL

Gap Junction

Consists of proteins surrounding a pore that allows the passage of material between cells

ANIMAL CELL

Plasmodesma (pl. plasmodesmata)

an open channel through the cell wall that connects the cytoplasm of adjacent cells