CH2 Cells

Cell theory

• base in the hierarchy of biological organization

• all organisms composed of cells

  • single-celled

  • multicellular

• all cells come from preexisting cells

Cell

• all share similar characteristics

• enclosed by membrane

• uses DNA for genetic info

• demonstrates correlation between structure and function

• form all body structures

• perform all body functions

• produced by division of preexisting __

• two types: gametes and somatic

Nonmembranous organelles

Microvilli, free ribosomes, centriole, centrosome, fixed ribosomes, cytoskeleton

Membranous organelles

Secretory vesicles, mitochondrion, golgi apparatus, peroxisome, nucleus, rough endoplasmic reticulum, smooth endoplasmic reticulum, lysosome

Nuclear components

Nucleoplasm, chromatin, nuclear pores, nucleolus, nuclear envelope surrounding nucleus

Phospholipids

Main structural component of membranes

• have a hydrophilic head and two hydrophobic tails

Plasma membrane

• cell to cell communication, structural support, adhesion

• regulates exchange with extracellular fluid

• physical barrier

• senses extracellular stimuli

• Phospholipids, proteins, glycolipids, sterols

Small, uncharged

What kinds of molecules move freely across membrane

• ex. CO2, O2, glycerol and alcohol

• driven by concentration gradient

Polar

What is the polarity of water

Aquaporins

Special channels that allow water to cross the membrane

Osmosis

diffusion of water

Diffusion

movement of solutes

Molarity

Concentration = mol/L

J = DA * (delta)C/(delta)X

Fick’s 1st law of diffusion

• J = rate of diffusion

• A = surface area for diffusion

• D = diffusion coefficient

• (delta)C = difference in solute concentration

• (delta)X = diffusion distance; membrane thickness

True

Gases can diffuse through a membrane? True/False

Passive transport

Simple diffusion, carrier-mediated diffusion, channel-mediated diffusion, osmosis diffusion of water via aquaporins

Active transport

Uses ATP to move solutes against concentration gradient

Cytoplasm

Organelles - membranous/nonmembranous

Cytosol

• Higher concentration of K+ ions and lower concentration of Na+ ions as compared to ECF

• Intracellular negative charge, extracellular is positive

• Contains high concentration of protein

• Contains a small quantity of carbohydrates

• Contains a large reserve of amino acids and lipids

Cytoskeleton

Microfilaments, intermediate filaments, microtubules

Microfilaments

• actin

• inner edge of cell

Intermediate filaments

• anchor organelles

• throughout cell

• transport materials

Microtubules

• move organelles

• cell movement

• essential for mitosis

• form centrioles, cilia, flagella

Ribosomes

• Free ___: float in cytoplasm

• Attached ___: on endoplasmic reticulum

• Synthesize proteins using ___ template

Mitochondria and nucleus

Both have double-layered membranes

Mitochondria

Site of ATP synthesis, oxidative phosphorylation

Nucleus

• nuclear envelope

  • nuclear pores

• nucleoplasm

  • nucleoli: make ribosomes

  • chromatin: loose coils of chromosomes

Endoplasmic reticulum

• synthesis

• storage

• transport

• detoxification

Rough endoplasmic reticulum

• attached ribosomes

• stores and synthesizes proteins

  • moved via transport vesicles

Smooth endoplasmic reticulum

• synthesizes lipids, steroids, and carbohydrates

• storage of Ca++

• Detoxification of toxins

Golgi apparatus

• synthesis and packaging of secretions

• packaging of enzymes for use in cytosol

• renewal and modification of cell membrane

Lysosome

vesicle filled with digestive enzymes

Peroxisome

vesicle filled with “house keeping” enzymes: oxidase, catalase

Endomembrane system

Golgi & ER, lysosomes, peroxisomes