Cells Chp. 4 AP Bio Cann

Types of Cells

• Prokaryotes

• Eukaryotes

Prokaryotes

• Domain Bacteria and Archaea

• No nucleus 

• DNA in a nucleoid 

• Cytosol

• No organelles other than ribosomes 

• Small size

• Primitive

Eukaryotes

• Protist, Fungi, Plants, Animals

• Have nucleays and nuclear envelope

• Cytosol

• Membrane-bound organelles with specialized structure

• Much larger in size

• More complex

Surface Area (SA)

• Large SA allows increase rates of chemical exchange

• Cells need large surface are to volume ratio

Villi

Finger like projections on small intestine wall

Microvilli

projections on each cell

Examples for Surface Area

• Animal: Small intestine, highly folded surface to increase absorption of nutrients

• Plant: Root hairs, extensions of root epidermal cells; increase surface area for absorbing water and minerals 

Nucleus

• Function:control center of the cell

• Contains DNA (and mRNA), nuclear pores, chromatin, and nucleolus 

• Surrounded by double membrane (nuclear envelope) 

  • continuous with rough ER

Nuclear pores

Control what enters/ leaves nucleus

Chromatin

COmplex of DNA and proteins; makes up chromosome

Nucleolus

Region where ribosomal subunits (rRNA + proteins are formed)

Ribosome

• Function: Protein synthesis

• Composed of rRna and protien 

• Large subunit and small subunit 

• 2 types

  • Free and bound 

Free Ribosome

• Float in cytosol, produce proteins used within cell

Bound Ribosomes

• Attached to ER, make proteins for export from cell

Endomembrane System

Regulates protein traffic and performs metabolic functions

Endoplasmic Reticulum

• Network of membranes and sac

• Types: Rough ER and Smooth Er

Rough ER

• Ribosomes on surface 

• Runction: package proteins for secretion send transport vesicles to Golgi, make replacement membrane 

Smooth ER

• No ribosomes on surface

• Function: synthesize lipid, metabolize carbs, detox drugs and poisons, store Ca2+

Golgi Apparatus

• Function;: Synthesis and packaging of materials (Small molecules) for transport (in vesicles); produce lysosomes

• Series of flattened membrane sacs (cisternae)

  • Cis Face: receives vesicles 

    • Chris receives vanilla

  • Trans Face: ships vesicles

    • Trina ships vanilla 

Lysosomes 

• Function: intracellular digestion; recycle cell’s materials; programmed cell death (apoptosis)

• Contains hydrolytic enzymes 

Phagocytosis

• process by which a cell (phagocyte) engulfs and digsts particles particles like bacteria, dead cells and debris

Autophagy

• Body;s natural process of self-cleaning, cell break down and recycle their own damaged or old components, like proteins and organelles 

Vaculoles

• Function: storage of materials (foo, water, minerals, pigments, and poisons)

• Membrane-bound vesicles

  • food vacuoles, contractile vacuoles

• Plants : large central vacuole → stores water and ions; retains water for turgor pressure (pressure of water against cell wall to maintain shape and rigidity of plant cells)

Mitochondria

• Function: site of cellular respiration 

• Fouble membrane: outer and inneer membrane 

• Cristae

• Matrix

Cristae

Folds of inner membrane; contains enzymes for ATP production; increase SA to increase ATP made

Matrix

fluid-filled inner compartment

Chloroplasts

• Functions site of photosynthesis

• Double membrane 

• Thylakoid disks in stacks (grana); stroma (fluid)

• Contains chlorophylls (pigments) for capturing sunlight energy 

Peroxisomes

• FUnctions: break down fatty acids: detox alcohol 

• Involves production of hydrogen peroxide (H202

Cytoskeleton

• Network of protein fibers

• Function: support, motility, regulate biochemical activities

• ex. actin, keratin, microtubules, microfilaments, and intermediate filaments

Centrosomes (aka microtubule organizing center)

• Region from which microtubules grow 

• Animal cells contain centrioles 

Cilia

Short and numerous; locomotion or move fluids

• covering entire surface of the cell

Flagella

• long and few; propel through water

  • one of few points on cell

Plant cells

• Cell wall: protect plant, maintain shape

  • composed of cellulose

• Plasmodesmata

  • channels between cells to allow passage of molecules from cell to cell 

Extracellular Matrix (ECM)

• Function: Strengths tissues and transmits external signals to cell

• Outside plasma membrane of animal cells

• COmposed of glycoproteins

  • ex. collagen

Plant Cell ONLY

• centeral vaculoles 

• Chloroplasts

• cell wall of cellulose

• plasmodesmata

Animal Cells ONLY

• Lysosomes

• Centrioles

• Flagella, culla

• Desmosomes, tight and cap junctions

• Extracellular Matrix (ECM)