Microscopes. Field of View Fly’s Foot Surface of an Erasable Programmable Read-Only Memory Silicon...

Microscopes

Field of View

Fly’s Foot

Surface of an Erasable Programmable Read-Only Memory

Silicon microchip

Eyelash hairs growing from the surface of human skin

The surface of a strawberry

Bacteria on the surface of a human tongue

Human sperm (spermatozoa)

Nylon hooks and loops of Velcro

Household dust: includes long hairs of cat fur, twisted synthetic and woolen fibers,

serrated insect scales, a pollen grain, and plant and insect remains

The weave of nylon stocking fibers

The head of a mosquito

Head louse clinging to a human hair

Eight eyes (two groups of four) on the head of a tarantula

Cut human hairs and shaving foam between two razor blades

Cigarette paper the tobacco is rolled in

Corroded surface of a rusty nail

Mushrooms spores

Clutch of butterfly eggs on a raspberry plant

Calcium phosphate crystal

Spider Skin

Starch in a corn kernel

Intestinal Bacteria

Paramecium

Volvox

Hooke

Prokaryotes

Link to Cell Size

Eukaryotes

FluidMoasicModel

http://multimedia.mcb.harvard.edu/anim_innerlife.html

Nucleus

Nucleus

• Contains the genes that control the cell; localizing the cell’s DNA

• Nuclear envelope

- separates the nucleus contents from cytoplasm

- double membrane with pores to regulate what enters and exits nucleus

Nucleus

• Nucleolus – densely packed RNA and proteins that makes up ribosomes

• Chromatin: threads of DNA that makes up the chromosomes and their associated proteins (histones)

Endomembrane System• Membranes physically touch one another

or transfer membrane segments through tiny vessicles

• Includes:- Nuclear envelope- Endoplasmic reticulum- Golgi apparatus- Lysosomes- Peroxisomes- Cell membrane

ER + Ribosomes

Endoplasmic Reticulum

• Membranous labryinth extending from the nuclear membrane

• Made of tubes and sacs called cisternae

Rough ER: ribosomes stud the cytoplasmic surface

• Many types of specialized cells secrete proteins made by the rough ER which are moved in transport vesicles

• As the polypeptide chain grows from the ribosomes, it goes into the ERs cisternal space and folds into higher levels

• Some proteins (glycoproteins) are covalently bonded to carbohydrates or are embedded in newly synthesized lipid membranes

Smooth ER: cytoplasmic surface lacks ribosomes

• Function:

- synthesis of phospholipids and steroids

-carbohydrate metabolism,

-detoxification of drugs/poisons

Ribosomes

• Sites where cells assemble proteins according to genetic instructions

• Free ribosomes are suspended in the cytoplasm which make proteins that will function in the cytosol

• Bound ribosomes are attached to the endoplasmic reticulum which make proteins that be included in membranes or transported outside the cell

Golgi Bodies

Golgi Apparatus

• Flattened, inner-connected membranous sacks with cisternae

• Products of ER are modified, stored, and shipped via transport vesicles

• Secretory vesicles have “docking sites” that recognize the surface of specific organelles

Lysosome

• Membrane-enclosed bag of hydrolytic enzymes that digests macromolecules

• Works best in an environment with pH = 5

• Amoeba eat via phagocytosis = engulf food then digest as the lysosome fuses to it

• Usually only found in animals

Animation: Lysosomes

Lysosome

Peroxisome

Peroxisome

• Contains enzymes that transfer hydrogen from various substrates to oxygen, producing H2O2

• The H2O2 is then converted into water

• Helps breakdown fats to be used in mitochondria for energy

• Detoxify alcohol in the liver

Mitochondria

Mitochondria

• Site of cellular respiration which generates ATP from sugars and fats

• Have ribosomes and small amounts of DNA for its own protein synthesis

• 100s-1000s per cell which correlate to the metabolic activity of the cell

• Enclosed in phospholipid bi-layer with inner foldings called cristae

Chloroplasts

Chloroplasts• Convert solar energy into chemical energy

by absorbing sunlight and using it to synthesize glucose from CO2 and H2O.

• Plastids: specialized organelles in plants- Leucoplasts: store starch in roots and tubers- Chromoplasts: enriched in pigments that give plants their colors- Chloroplasts: contain the green pigment cholorphyll

• What organelle is taking up most of the space in this plant cell?

Vacuole

• Central vacuole: stores water, organic compounds, ions, wastes, and hydrolytic enzymes

• Tonoplast: membrane surrounding plant vacuole

• Vacuoles and vesicles are both membranous sacs, but vacuoles are larger

Cytoskeleton

Cytoskeleton• Network of fibers that allow for material

movement within the cell• microtubules – larger filaments that help

• move organelles during cell division • form hair-like extensions on cell surface for

movement (cilia or flagella)• Centrioles – rings of microtubules which form

spindle fibers to aide in cell division

• Microfilaments (actin) – smaller filaments that maintain shape and aid in muscle contraction

Centriole

Flagella

Cell Wall

• Made of cellulose (polysaccharide) not digested by most animals

• Rigid structure that supports and protects plant cell by preventing the excess uptake of water- turgor pressure from vacuole assists in support

• Allows movement of materials in/out of cell through plasmodesmata (channels)

Cytoplasm

• Cytosol: semi-fluid medium in which organelles are suspended

• Mostly water but also contains ions, sugars, amino acids, RNA, and ATP (cell energy)

Harvard Cell Animation/

Plasmolyzed Flaccid Turgid

Animation of Endo/Exocytosis

Exocytosis