Cell Theory, Microscopes, Eukaryotes and Prokaryotes. IB Biology Unit 1

Outline functions of life

Metabolism, reproduction, sensitivity, homeostasis, excretion, nutrition, growth/movement

Metabolism

essential chemical reactions(cellular respiration/photosynthesis)

Reproduction

produce offspirng (sexually or asexually)

Sensitivity

responsive to internal and external stimuli(flinching)(light sensitivity)

Homeostasis

maintain a stable internal environment(temperature control)

Excretion

removal of waste products(photosynthesis)

Nutrition

exchange materials and gases with the environment (urine) cellular(getting rid of CO2)

Growth / Movement

move and change shape or size

Cell theory

Living organisms are composed of cells,Cells are the smallest unit of life,Cells come from pre

Unicellular organisms

carry out functions of life by themselves

Multicellular organisms

cells work together to keep the entire organism alive

4 basic structures for all cells

Plasma Membrane, Genetic Material, Ribosomes, Cytosol

Plasma Membrane

outer border, Assists with homeostasis

Genetic Material

instructions controlling activities, DNA

Ribosomes

create proteins

Cytosol

internal fluid

Examples of atypical eukaryotic cells and tissues not conforming to cell theory

Striated muscle fibers, Aseptate fungal hyphae, Sleeve tube elements, Red blood cells

Striated muscle fibers

muscle cells fuse together forming long fibers. They are atypical due to Continuous plasma membrane and being multinucleated

Aseptate fungal hyphae (atypical features)

Continuous cytoplasm multinucleated

Sieve Tube Elements(plants) atypical features

Lack nuclei and few organelles

Red blood cells (animals) atypical features

No nucleus or mitochondria Cannot independently replicate

What can you not see with the naked eye

anything smaller than 0.1mm(most cells are smaller)

Types of microscopes

light and electron

Features of a light microscope

Living or dead specimens, Natural colors, Staining can be used(Fluorescent labeling and Immunofluorescence staining)

Fluorescent labeling

Synthetic dyes

Immunofluorescence staining

Uses antibodies with stains to see

Disadvantages of light microscopes

Cannot see really small objects

Electron Microscopes features

Nonliving specimens, High magnification and resolution (Coat with metal then shoot electron)

Types of Electron Microscope

Scanning electron (3d), Transmission electron(flat; cross section)

Features of transmission electron

Cryogenic electron microscopy, Freeze Fracturing

Cryogenic electron microscopy

Freezes sample without heavy metals

Freeze Fracturing

cracks along a plane, cutting it while frozen, Cell membranes seen this way

Magnification equation

M = Image size/actual size

Prokaryotes

Oldest cells (3.8 billion years ago), Small and simple,No compartmentalization(No membrane bound organelles) 70s ribosomes (size) Circular DNA, May have plasmid

Circular DNA

Generally lacks introns (noncoding DNA)

Plasmid

Smaller separate DNA loop

Domain classifications of prokaryotes

Bacteria, Archaea

Bacteria

Naked DNA (no histones), Many pathogenic, Most are susceptible to antibiotics

Archaea

DNA with histones extremophiles Can exist in normal habitats Not susceptible to antibiotics

Shapes of bacteria

Bacillus (rods), Coccus (spheres), Spirillus (spiral)

Know how to label baillus bacteria

Plasma Membrane

Controls what enters and exits

Cell Wall

maintains shape

Flagella

movement

70s ribosome

makes proteins

Slime capsule

protects from physical damage

Nucleoid

contains genetic information

Cytoplasm

suspends structures

Pili

allows for attachment

How do prokaryotes reproduce?

binary fission

Binary Fission

DNA copied in response to replication signal, 2 DNA loops attach to the plasma membrane, 2 identical cells formed by cytokinesis

Eukaryotic Kingdoms

Animalia, Plantae, Fungi, Protista

Eukaryotes

appeared 1.5 billion years ago, complex Compartmentalized (membrane bound organelles)

Advantages to compartmentalization in cytoplasm

All organelles can maintain own internal chemistry

Key Components of Eukaryotes

DNA found in nucleus is linear and has multiple chromosomes, 80s ribosomes, Organelles

Eukaryotic organelles

Discrete subunits of cells adapted to perform specific functions

Nucleus

Stores genetic information, Linear DNA wrapped around histone proteins, Has pores in double membrane

Advantages to separation of nucleus and cytoplasm

Gives cell greater control over transcription and translation

Transcription

DNA template for making mRNA(nucleus)

Translation

mRNA read to make polypeptides(cytoplasm)

Mitochondria

Aerobic cellular respiration/ Site of ATP production, Double membrane, 70s ribosomes, Naked circular DNA of maternal origin

Endoplasmic Reticulum (ER)

Series of membrane channels, 2 Types (smooth and rough)

smooth endoplasmic reticulum (SER)

no ribosomes and Lipid synthesis

rough endoplasmic reticulum (RER)

Bound 80s ribosomes Creates secretory proteins(proteins to exit cell)

Golgi Apparatus

Flattened, stacked, membrane sacs near plasma membrane and it manufactures, modifies, and packages secretory proteins

Vesicles

Membranous containers Transport and store materials.Peroxisomes, Lysosomes, Vacuoles

Peroxisomes

break down toxins

Lysosomes

breakdown cellular waste(animals only)

Vacuoles

store excess fluid

Chloroplasts

Site of Photosynthesis, Double membrane, 70s ribosomes, Naked circular DNA

Plant Cell Wall

Protects and supports cell, Made of cellulose, a complex carbohydrate(polysaccharide), Extracellular component(Beyond the plasma membrane)

Centrosome(Unique to Animals)

Contain paired centrioles Assist with cell division

Plant Cell

Nutrition:Autotroph,Cell Wall: Cellulose,Vacuoles: Large(permanent), Motility: None

Animal Cell

Nutrition: Heterotroph(ingestion), Cell Wall: None, Vacuole: Small(Temporary), Motility: Flagella, Cilia

Fungi Cells

Nutrition: Heterotroph(absorption), Cell Wall: chitin, Vacuole: Large(permanent), Motility: None

Similarities of Prokaryotes and Eukaryotes

Plasma membrane, Ribosomes, DNA, and cytoplasm

Prokaryotic differences

Naked DNA(no histones), Circular DNA, DNA in "nucleoid", Not compartmentalized 70s ribosomes Reproduction: Binary Fission

Eukaryotic differences

DNA wrapped around Histones, Linear DNA, DNA in nucleous, Compartmentalized, 80s ribosomes, Reproduction: Mitosis or Meiosis