Cells

Prokaryotes

•Are smaller and simpler than eukaryotes•They don’t have a nucleus their genetic

material is contained with in the cell•Even though they are very simplistic they

still do a variety of things: grow, reproduce, respond to the environment.

•The domains Bacteria and Archaea are Prokaryotes

Parts of a Prokaryote Cell

• Cytoplasm- portion of the cell outside of the nucleus

• Cytosol-liquid substance• Ribosomes- organelles that synthesize protein• Nucleoid- hold the DNA but doesn’t have a

membrane• Plasma Membrane- membrane enclosing the

cytoplasm, selective barrier• Cell Wall- rigid structure outside the plasma

membrane• Capsule- jelly like outer coating of many

prokaryotes• Flagella- locomotion organelles of some bacteria

Eukaryotes

•There are two types of Eukaryotes▫Heterotrophs or Animal cells▫Autotrophs or Plant cells

•Generally larger and more complex than prokaryotes.

•Contain dozens of internal structures and membranes

•Contain a nucleus in which their genetic information is stored separate from the rest of the cell.

Structures found only in Plant Cell

• Cell Wall-outer layer that maintains cell’s shape and protects the cell from mechnical damage; made of cellulose, other polysaccharides, and protein. ▫The the cell wall is on the outside of the cell

membrane▫Most are porous enough to let water H2O, oxygen O2,

and carbon dioxide CO2

• Chloroplast- photosynthetic organelle• Central Vacuole- prominent organelle functions

include- storage, breakdown of waste products, hydrolysis of macromolecules; enlargement indicates plant growth

• Tonoplast- membrane enclosing the central vacuole• Plasmodesmata- channels through cell walls that

connect the cytoplasms of adjacent cells

Structures found only in Animal Cell

• Lysosomes- they are filled with enzymes. Their function is the breakdown (hydrolyzed) or digestion of lipids, carbohydrates, and proteins to make them into something useful in the cell. They also digest old worn out organelles they get rid of the junk.

• Centrioles- are located by the nucleus and help with cell division.

• Flagella-locomotion organelle present in some animal cells, composed of membrane enclosed microtubules

Structure Found In Both Eukaryotic Cells

•Organelles- little organs•Cytoplasm- portion of the cell from the

nucleus to the plasma membrane•Cytosol-liquid substance with in the

cytoplasm•Nucleolus- helps with ribosome production, it

is nonmembranous•Nucleus- controls most cell processes and

contains the hereditary information of DNA, membrane bound, contains the nucleolus with in.

•Nuclear Envelope (membrane)- surrounds the nucleus, double membrane bound, perforated by pores, and is continuous with the ER

•Chromatin- is a granular material in the nucleus that consists of DNA bound protein. Is visible as chromosomes in cell division.▫Chromosomes- threadlike structures

containing genetic information •Plasma Membrane- membrane enclosing

the cell. It is made of a lipid bilayer.•Ribosomes- small particles of RNA and

protein in the cell. They make proteins, nonmembranous, free floating in the cytoplasm and can be bound to the rough ER or the nuclear envelope

•Endoplasmic reticulum (ER)-is a network of membranous sacs and tubes; active in membrane synthesis and other synthetic and metabolic processes▫Rough ER- is a section of the ER covered in

ribosomes this is the section where proteins are changed and packaged

▫Smooth ER- I s a section of the ER not covered in ribosome. It has special functions like making lipids, metabolism of carbohydrates, and the detoxification of drugs and poisons.

•Golgi Apparatus- is where things are modified, synthesized, sorted, and packaged, to either be used in the cell or get sent outside the cell.

•Mitochondria- the “power house”. This is where ATP is made, and energy is stored. •Both mitochondria and chloroplasts contain

their own DNA•Cilia- helps with movement of the cell or moving things across the cell

•Cytoskeleton- reinforces cell’s shape, functions in cell movement; components are made of protein▫Microfilament-part of the cytoskeleton as

well as cilia and flagella. Helps with shape and support

▫Microtubules-contains the motor protein that contracts to help the cell move

▫Intermediate filaments

•Microvilli- projections that increase the cell’s surface area

•Vacuoles- store material such as water, salt, proteins, and carbohydrates.

•Peroxisomes- has a variety of specialized metabolic functions; contain enzymes that produces hydrogen peroxide.

•Centrosome- region where the cell's microtubules are initiated and in animal cells it contains a pair of centrioles (Plants lack centriols)

Plant Cells

Animal Cells

Cell Membrane•Cell Membrane/plasma membrane- thin flexible

barrier that surrounds all cells. This separates the inside of the cell with the outside world▫Regulates what enters and exits the cell/

transport ▫Provides protection and support▫Composed of a lipid bilayer▫In the bilayer there are protein channels/ pumps,

carbohydrate markers▫Membrane proteins can move with in the

membrane▫Membrane must be fluid to work properly▫Phospholipids form the main fabric of the

membrane but proteins determine most of the membranes functions

•Integral proteins- they are coiled into alpha (α) helices

•Peripheral proteins- not embedded, loosely bound to the surface of the membrane or to the integral proteins▫Glycolipids- carbs bonded to lipids▫Glycoproteins- carbs bonded to protein

•Concentration Gradient•Membrane potential- is the charge across

the membrane. Cytoplasm is negative•Cotransport- ATP powered pump that can

indirectly drive another reaction

•Toncity- the ability of a solution to cause a cell to gain or lose water▫Isotonic▫Hypertonic- to the cell means that the cell will

lose water to it environment▫Hypotonic- to the cell means the cell will gain

water (lyse)▫Turgid- firm, hypotonic, in plant cells▫Flaccid- limp, isotonic, plant cells▫Plasmolysis- wilt, hypertonic, plant cells

•Osmoregulation- happens in cells without rigid cell walls these help control the water balance

•Exocytosis- the cell secretes•Endocytosis- the cell takes in

▫Phagocytosis- eating▫Pinocytosis- drinking▫Receptor mediated- enables the cell to

acquire bulk quantities of a specific substance

•Ligands- general term for any molecule that binds specifically to a receptor site of another molecule

6 functions of proteins• Transport

▫Channels- carrier proteins, aquaporins▫Pumps- electrogenic -(generates voltage across

membrane) proton-(transports protons to generate a voltage)

▫Passive▫Active

• Enzymatic activity- proteins built into the membrane with active site exposed

• Signal transduction- active site with a specific shape that fits the shape of a chemical messenger

• Cell-to-cell recognition- ID tags for other cells• Intercellular joining- help hook cells together• Attachment to the cytoskeleton & ECM (extracellular

matrix)

ECM•Most of the cells in multicellular

organisms are surrounded by a complex mixture of nonliving material that makes up the extracellular matrix

•It consists of protein fibers