Cellular Structure

Cell Biology / Genetics

Mr. Foster

Components of Cells

1. Nucleus-

2. Outer Boundary-

3. Cytoplasm/Organelles- cellular contents and specialized structures that carry out functions of the cell

Nucleus

• Prokaryote- cell w/o nucleus – (DNA in neucleoid)

• Eukaryote- cell with nucleus

• Functions– Contains genetic inform.– Control Center- directs all

cellular activity

Nucleus (cont.)

• Structure / Components-– Nuclear envelope- regulate

what enters and leaves nucleus (Nuclear pores)

– Nucleolus-makes ribosomes– Genetic Material- DNA

• Chromatin – DNA uncoiled, threadlike, Not Divisional

• Chromosomes –DNA is condensed, Divisional

– Nucleoplasm -fluid inside nucleus

Clicker ?’s 1-5

Outer Boundary

• Cell membrane-lipid bilayer with embedded proteins forming a selective boundary

• All cells have a cell membrane

• Cell wall –

Plants and bacteria

Cell Membrane (cont.)

• Structure- Fluid Mosaic Model1. Phospholipids

• Phospholipid bilayer

forms membrane

Lipid- does not like H2O (hydrophobic)

Phosphate- likes H2O (hydrophilic)

• Structure (cont.)2. Proteins

Integral Proteins - embedded in phospholipid bilayer

Peripheral protein –

not embedded in bilayer

Cell Membrane (cont.)

Clicker ?’s 6-9

• Structure (cont.)3. Carbohydrates - attach to proteins (glycoprotein)

or lipids (glycolipid)

Cell communication –

recognize cell type

Cell Membrane (cont.)

• Structure (cont.)

4. Cytoskeleton –supports the membrane

a. microfilaments -strength, anchor cells

b. microtubules – mvmt.

c. intermediate filaments –not always present, a lot in skin, strong framework

(Disease where cells collapse: pg 31)

Cell Membrane (cont.)

Cytoskeleton

• Functions– Support and protect cell

– Communicate with other cells

– Controls mvmt. of materials in and out of cell.• Selectively Permeable

Clicker ?’s 10-13

Cell Transport

• Passive – energy not required to move material across membrane– Diffusion – molecules move from high to low

concentration to reach equilibrium

– Osmosis – type of diffusion involving H2O molecules only

Cell Transport (cont.)

• Active – Energy required to move materials across membrane

Low to High concentration– Ion pumps/Channels- Cl-, Na+, K+, Ca+

– Endocytosis / Exocytosis –

membrane forms pockets to

move material

Ion pumps

Endocytosis / ExocytosisClicker ?’s 14-17

Cytoplasm / Organelles

• Cytoplasm – space between nucleus and cell membrane– Cytosol – semitransparent; jellylike substance that

surrounds organelles

• Organelles – “little organ”

Organelles• Endoplasmic Reticulum-

– Transports materials through inside of cell

– Modifies proteins and quality control center

• Types of ER– Rough ER

• Has ribosome attached• Proteins to be sent outside cell

– Smooth ER• No ribosomes• Make lipids, detox cell

Smooth or Rough?

Organelles (cont.)• Ribosome-

– Synthesize proteins– Free vs. attached

• Mitochondria– Provides energy for the cell ATP

• Cellular respiration

– Own DNA– Endosymbiont Theory

• Free living organism that

entered a relationship w/

Nucleated cells

– Inherited from mother only– Folds increase surface

area

Organelles (cont.)

Organelles (cont.)

• Golgi Apparatus - (Golgi bodies) modifies, sorts, and ships proteins in packages called vesicles.

What is this?

Clicker ? 18-22

Organelles (cont.)

• Lysosomes– Membrane bounded sacs that contain enzymes– Clean up cell– Lysosomal Storage disease

(Tay Sachs)- missing the

enzyme that breaks down the

lipid that surrounds the nerve

cell

Buries the nervous system

• Peroxisomes– Sac that contain enzymes

that detoxifies harmful

products

– H2O2 H2O

– Alcohol– Abundant in liver cells

Organelles (cont.)

• Centrioles– Composed of microtubules– Contained in specialized

region = centrosome– Function in cell division

• Organize spindle fibers

Organelles (cont.)Clicker ? 23-26