Chapter 3 -Chapter 3 - Cells and TissuesCells and Tissues

Cell Anatomy

Cells and TissuesCells and TissuesCarry out all chemical

activities needed to sustain life

Cells - the building blocks of all living things

Tissues - groups of cells that are similar in structure and function

Anatomy of the CellAnatomy of the Cell

Cells not all the same, but share general structures

3 main regions

- Nucleus

- Cytoplasm

- Plasma membrane

The NucleusThe Nucleus

Control center

- Contains (DNA)

3 regions

- Nuclear membrane

- Nucleolus

- Chromatin

Nuclear Envelope (Membrane)Nuclear Envelope (Membrane)

Barrier of nucleus

Made of double phospholipid membrane

Pores allow for exchange of material with rest of the cell

NucleolusNucleolus

Nucleus contains 1 or more nucleoli

Make ribosomes

Ribosomes migrate to cytoplasm through nuclear pores

DNA – DNA – Chromatin & Chromosome FormsChromatin & Chromosome Forms

Composed of DNA and protein

Chromatin - throughout nucleus in thread form

Chromosomes -condensed DNA forms before cell divides

CytoplasmCytoplasm

Material outside nucleus and inside plasma membrane

1. Cytosol

Fluid that suspends other elements

2. Organelles

Machinery of cell

3. Inclusions

Non-functioning units

Cytoplasmic OrganellesCytoplasmic Organelles

1. Ribosomes Made of protein and RNA (made in nucleolus)

Sites of protein synthesis

Found at two locations

1. Free in the cytoplasm and

2. Attached to rough endoplasmic reticulum

2. Endoplasmic reticulum (ER) Fluid-filled tubules for carrying

substances

Two types

- Rough ER

- Studded with ribosomes

- Makes parts for membranes

- Smooth ER

- Makes & breaks cholesterol

- Fat metabolism

- Detoxifies drugs

3. Golgi apparatus Modifies and packages proteins (3 types)

- Secretory vesicles

- Cell membrane components

- Lysosomes

4. Lysosomes

- Sacs of enzymes

- digest nonusable materials

5. Peroxisomes

- Sacs of oxidase enzymes

- Detoxify harmful substances

- Break down free radicals (highly reactive chemicals)

- Replicate by pinching in half

- Remember bubbling liver?

6. Mitochondria

“Powerhouses” of the cell

Change shape continuously

Uses O2 to break down food

Provides ATP for energy

Three different types

Microfilaments

Intermediate filaments

Microtubules

7. Cytoskeleton• Protein structures throughout the cytoplasm

• Internal framework

8. Centrioles

Rod-shaped bodies made of microtubules

Make spindle fibers during cell division

Plasma MembranePlasma Membrane Barrier for cell contents

Double phospholipid layer

- Hydrophilic heads

- Hydrophobic tails

Other materials in membrane

- Proteins

- Cholesterol

- Glycoproteins

Plasma Membrane SpecializationsPlasma Membrane Specializations Microvilli

- Finger-like projections

- Increase surface area for absorption

Membrane junctions

- Tight junctions - impermeable

- Desmosomes - anchor

- Gap junctions - communicate

Cellular ProjectionsCellular Projections Not found in all cells

Used for movement

- Cilia move materials across the cell surface

- Flagellum propels the cell