GZOO UNIT 3

Cell Theory

Every living organism is constructed from cell

Cell Theory

A foundational principle

Cell Theory

• According to this theory:

1. All life consists of cells

2. Cells are basic units that possess all characteristics of living organism

3. Creation of new cells can only occur through division of existing cells

Cell Theory

Made over three centuries ago

Cell Theory

Remain a source of fascination and ongoing research

Cell biology

Highly dynamic field of investigation

Cell biology

Providing insight to fundamental questions about how organisms operate

Cellular functions

• Gain insights into potential treatments for human ailments, like cancer and AIDS

Homeostasis

Balance in human body

Cell Membrane

• Phospholipid bilayer containing many different molecular components

Cell Membrane

Proteins, cholesterol, some with carbohydrate groups attached

Phospholipid bilayer

• Consists of two adjacent sheets of phospholipids arranged tail to tail

Hydrophobic tails

Associate with one another, forming interior of membrane

Hydrophobic tails

Polar heads contact fluid inside and outside of cell

Glycoprotein

Glycoprotein

protein with carbohydrate

Glycolipid

Glycolipid

lipid with carbohydrate

Peripheral membrane protein

Integral membrane protein

Cholesterol

Channel protein

Phospholipid bilayer

Extracellular

Intracellular

Phospholipid bilayer

Hydrophobic tail

Hydrophilic head

Transport proteins

Allows particular substances

Transport proteins

Specific ions (sodium-potassium pump for Na+ and k+)

Transport proteins

• /molecules (aquaporins for water)

Transport proteins

Move in and out of cell selectively

Enzymes

Act as catalysts expediting chemical reactions within cell

Receptors

selectively bind to specific molecules outside the cell, initiating subsequent chemical reactions within cell

Receptors

Subtype of recognition proteins

Attachment points for cytoskeleton

Anchors for cytoskeleton proteins

Attachment points for cytoskeleton

Provide stability and support

Cell recognition proteins

Play a role in identifying cell’s unique identity, allowing it to be recognized by other cells

Glycoproteins

Cell recognition proteins that determine blood types

Glycocalyx

Cell recognition proteins that has Cellular “name tag”

Mitochondria

Plasma mebrane

Microtubule

Centriole

Microfilament

Lysosome

Smooth endoplasmic reticulum

Secretory vesicle

Peroxisome

Vacuole

Cytoplasm

golgi vesicle

Golgi apparatus

Chromatin

Nucleus

Rough endoplasmic reticulum

Ribosomes

Intermediate filament

Cell membrane

• Entry and exit of substances from cell

Cell membrane

• Aids in helping cell identify itself to molecules and other cells

Nucleus

Site of transcription of mRNA

Nucleus

Stores and protects DNA

Chromatin

Condense during prophase of cell cycle -> chromosomes

Chromatin

Thin, loosely coiled “threads” of DNA wound around histone proteins

Nucleolus

Synthesizes rRNA

Nucleolus

Performs some ribosome assembly

Nuclear envelope

Lipid-bilayer

Nuclear envelope

Surround and protect contents and processes of nucleus

Nucleus

Store and protect DNA

Nucleus

Site of mRNA prescription

Gel-like watery matrix of cell

Site of anaerobic cell respiration and other chemical reactions

Cytoplasm: Site of anaerobic cell respiration and other chemical reactions like

• Bicarbonate buffering system

cytoplasm Stores molecules like…

Glucose

CytoplasmCushions and contains organelles is

Composed of 50% water

• Cytosol

Only gel-like watery matrix +

• Cytoplasm Nucleolus 

Synthesizes RNA;

• Cytoplasm Nucleolus

perform ribosome assembly

Smooth ER

Stores calcium in muscle cells

ER

Endoplasmic Reticulum)

Sarcoplasmic reticulum

• Muscle cells

Smooth ER (Endoplasmic Reticulum)

• Manufactures phospholipids

Sarcoplasmic reticulum

Synthesizes proteins for secretion

Sarcoplasmic reticulum

• In liver cells, perform lipid and cholesterol manufacturing

Rough ER

• Synthesizes and modifies proteins for cell membrane or for export from cell

ROUGH ER: Glycosylation of protein

One form of modification

Golgi apparatus

‘Golgi complex’, ‘Golgi body’

Golgi apparatus

Sort, modify, package (in vesicles)

Golgi apparatus

Distribute lipids and proteins

Lysosome

Uses hydraulic enzymes to degrade:

Lysosome hydraulic enzymes to degrade:

1. Worn out organelles

2. Glycogen

3. Bone matrix

4. Harmful items

Lysosome harmful items

Poisons or bacteria

Peroxisome

Use enzymes to detoxify cell

Peroxisome Use enzymes to detoxify cell of

1. Medications

2. Alcohol

3. Cancer causing agents

4. Pesticides

Peroxisome pesticides is in

liver and kidney cell

Enzymes within Peroxisome

Transfer hydrogen atoms from molecules to oxygen

Enzymes within Peroxisome

• Produce hydrogen peroxide (H2O2), to neutralize poisons: alcohol

H202

Hydrogen peroxide

Peroxisome poisons like..

alcohol