cell structures. cell structures barriers… cell wall plants & prok. (not animals) plants...

Cell Structures

Cell Structures

Barriers… Cell Wall

Plants & prok. (not animals)Structural (plant support) & protective

roleCellulose in plantsFreely permeable

Cell walls of onion skin…

Barriers…Cell Membrane (plasma membrane)

In ALL cells

Support/protection Regulates movement in/out of:

WaterNutrientsWaste products

Cell Membrane...

Barriers…Nuclear Envelope (nuclear membrane)

Surrounds nucleus

Thousands of poresMaterial move in/out, incl. RNA

Nuclear envelope

Fluids…Cytoplasm (cytosol)

Bet. cell mem. and nuclear env., site of most chemical activity

NucleoplasmSemi-fluid medium of nucleus

ProtoplasmTerm used for all substances inside cell

The Control Center

The Nucleus

The Nucleus…Controls most cell processes

Contains ChromatinDNA bound to proteins

During cell division, condenses to Chromosomes…

Has a NucleolusSmall, dense region

Assembly of Ribosomes

Nuclear Envelope (or membrane)

Little Organsassist the cell in conducting

reproductive, respiratory, and structural needs

Organelles of the

cytoplasm

Cytoskeleton… Protein filaments

Maintains cell shape

Involved in cell movement

Cytoskeleton

Mitochondrion…Uses energy from food

Makes high-energy compounds (ATP) needed for Rx elsewhere.

Ribosomes…Small, made of RNA (is an RNA molecule)

Assembly of proteins

Free in cytoplasm or attached to Rough ER

Endoplasmic Reticulum…

Large, assists with other organelle movement

Two types: Rough ER (RER)

○ Ribosomes stud surface○ Aids in synthesis and modif. of proteins○ Found wrapped around nucleus, extending into

cytosol Smooth ER (SER)

○ No ribosomes, attached to distal RER○ Synthesis of lipids, phospholipids, steroids (Plentiful in testes, ovaries, skin oil glands)

Golgi Apparatus…Receives proteins from rough ER

Enzymes attach carbs and lipids to the proteins

Can store proteins until needed

Proteins then sent to final destination(within cell or outside – exocytosis)

PACKAGING and SHIPPING

Golgi Apparatus

Vacuoles…Saclike structure

Stores water, salts, proteins, carbs

Can be large in plant cellsHelps in plant support by keeping turgor pressure high

Vacuoles

Vacuoles

Korotnovella, an amoeba. Inside this cell we can see a nucleus near the center with a rather angular dark nucleolus, various food vacuoles, and a clear round contractile vacuole at about 10 o'clock.

Lysosomes…Filled with enzymes (like H2O2)

Breaks down lipids, carbs, and proteins from food

old organelles

debris and harmful invaders

Video

Plastid 1: Chloroplasts…

In plants, not animals or fungi

Uses sunlight to make energy rich food mol. thru photosynthesis (psyn)

Chloroplasts…

Chloroplast

Plastid 2: Leucoplast

Sometimes called amyloplast; stores starch (amylose)

Plastid 3: Chromoplast

Stores pigments in plants

CentriolesCylindrical; group of microtubules

In animal cells, used in cell division

As “basal bodies,” form cilia and flagella

Cell membrane - Structure

A phospholipid contains-

one head; negatively charged phosphate group that is hydrophilic (water-loving)

two tails of fatty acid chains that are hydrophobic (water fearing)

The Cell Membrane

Made of a phospholipid bilayer

regulates what passes in/out

Supports and protects

Selectively permeable – only certain things pass through.

5 nm thick

Cell membrane features

The fluid mosaic modelfluid in nature cell mobilityWithin mem. are various proteins for:

enzyme activity,cell attachment,communicating with other cells, Trans. of substances in and out