chapter 3 cell biology & genetics

Part 1

Chapter 3Cell Biology & Genetics

Cells

Basic units of ALL living things Smallest part of an organism that have

the characteristics of life All eukaryotic cells have

Plasma membrane Nucleus Cytoplasm Organelles

cork cells

What do “cells” do?

Cellular Functions Undergo metabolic reactions

(metabolism) & Use Energy Synthesis of Molecules (proteins, nucleic

acids, lipids) Communication Reproduction & Inheritance

CELL CITY

Cell Video

Inner Life of a Cell

Cell Parts (page 58-59)PLASMA MEMBRANE

Function….. outer boundary of cells Controls the entry and exit of

substances Contain “receptor proteins” (name

tags) which identify the cells to recognize other cells (communication)

Plasma Membrane - Structure

Phospholipid bi-layer containing cholesterol molecules and proteins

Nucleus - Function

Control center of cell Houses the DNA (deoxyribonucleic

acid) which regulates protein synthesis (remember enzymes are a type of protein) & the chemical reactions that take place within the cell

Nucleus - Structure Enclosed by nuclear envelope

(double membrane) which has pores

Contains chromatin (DNA) Contains a nucleolus which is

where ribosomes are made

Ribosome - Function

Site of Protein Synthesis

Ribosome - Structure

Made of rRNA (ribosomal RNA) and proteins

Some ribosomes are found attached to endoplasmic reticulum and some are “free” floating in the cytoplasm

Rough Endoplasmic Reticulum (RER) - Function

Synthesizes Proteins and then transports them to the Golgi Apparatus

Rough ER - Structure

Membranous tubules and flattened sacs with attached ribosomes

Smooth Endoplasmic Reticulum (SER) - Function

Makes lipids and carbohydrates Detoxifies harmful chemicals Stores Calcium

Smooth ER - Structure

Membranous tubules and flattened sacs with no attached ribosomes

Golgi Apparatus (aka Golgi Body) - Function

Modifies, packages, and distributes proteins and lipids for secretion or internal use

Golgi Body - Structure

Flattened membrane sacs stacked on each other

Lysosome – Function & Structure

Function: contains digestive enzymes Structure : membrane bound vesicle

(pinched off from Golgi)

Peroxisome – Function & Structure

Function : site of amino acid and lipid breakdown & breaks down hydrogen peroxide

Structure: membrane bound vesicle

Proteasomes – Function & Structure

Function : Break down proteins in cytoplasm

Structure: tube-like protein complex in cytoplasm

Mitochondria - Function

Major site of ATP (energy) synthesis when oxygen is available

Mitochondria - Structure

Double membrane bound organelles Inner membrane forms “infoldings”

called cristae

Centrioles - Function

Site of microtubule formation Form the base of flagella and cillia

Centrioles - Structure

PAIR of cylindrical organelles in the centrosome (MTOC) consisting of triplets of parallel microtubules

Cilia - Function

Move materials over the surface of cells

Cilia - Structure

Extensions of the plasma membrane Contains DOUBLETS of parallel

microtubules 10 micrometers long

Flagella – Function & Structure

Propels spermatozoa (in humans) Extensions of plasma membrane

containing doublets of parallel microtubules

55 micrometers long

Cilia vs Flagella

Microvilli – Function & Structure

Function: Increase surface area of plasma membrane for absorption and secretion; modified form of sensory receptors

Structure: extensions of plasma membrane containing microfilaments