Phys Exam 2-1

• smallest living subdivision of human body
• diverse in structure and physiology
• divided into organelles
• -isolation of chemical reactions
• -each organelle performs a specific function

• plasma membrane
• cytoplasm
• nucleus

• outer boundary of cell
• seperates intracellular enviro from extracellular enviro
• regulates movement of materials into and out of cell
• -a selective barrier
• -helps maintain internal cell homeostasis

• composed of lipids, proteins, and carbohydrates
• -arranged in bilayer of phospholipids with proteins suspended
• -"fluid mosaic model"

polar heads face extracellular fluid and cytoplasm

nonpolar tails prevent random movement across the membrane

• found on apical surface of some hollow tube like organs
• fingerlike projections
• increase surface area
• facilitate movement of materials between intra and extracellular fluids

projects into extracellular fluid

contains microtubules, and uses ATP

capable of movement and generates flow

semi liquid, gel like-has a water solvent

surrounds organelles

contains various disolved materials, enzymes, etc

location for metabolic reactions

protein synthesis

storage of fat, glycogen, and secretory vesicles

• network of protein fibers in cytosol
• -microtubules
• -microfilaments

structual support and shape of cell

movement of materials inside the cell

• -external movement
• cilia and flagella
• amoeboid movement
• endocytosis and exocytosis(secretion)

membrane bound organelle with digestive enzymes

break down large molecules(cells digestive system)

destroy bacteria, old organelles

• surrounded by two cell membranes
• -inner membrane cristae and surrounds the matrix

posses own DNA

• power generators of cell
• -produces ATP using energy released from the breakdown of food

large protein-RNA complexes

found free floating in cytosol or attached to ER

synthesizes proteins based on triplets of mRNA molecules

Production of Protein

coated with ribosomes on cytosolic side

• synthesizes proteins for;
• cell membranes
• lysosomes
• export of the cell

No protein synthesis

No ribosomes

lipid synthesis

Ca+ storage and release

metabolize various molecules

• stacks of flattened sacs(cisternae)
• Functions:
• posttranslational modifications(finishing steps)

• sort and direct finished products to final destinations
• "directs traffic"

small membrane-enclosed chambers used to transport material within the cell

• -delivers membrane molecules
• -fluid within vesicle can be emptied into another organelle(lysosomes) or secreted into extracellular fluid(secretory vesicles)

control center-contains info for protein synthesis

surrounded by double membrane(nuclear envelope) with nuclear pores open to cytosol

• contains chromatin
• -DNA and assoc proteins
• -chromosome= strand of DNA
• nucleolus-synthesis of RNA

sequences of DNA containing info for amino acid sequence to make proteins

the total of all the genes in the human body(approx 25,000)

all the different proteins produced in the human body(approx 100,000)

genes can encode for more than one protein

not all genes in a genome are active (approx 300)

different types of cells express different sets of genes within the person's genome

transcription

encodes the structure for a particular protein

"reads the code on DNA"

carries amino acids to ribosomes to add into newly synthesized polypeptide

structural component of ribosomes

produced in nucleolus

translation

mRNA sequence read by ribosomes to generate a protein with a specific amino acid sequence

-ribosome binds to mRNA

-ribosomes reads triplets(codons)

-tRNA delivers specific amino acids

-amino acid is transferred from the tRNA to polypeptide chain

-ribosome reads next codon and repeats process

-polypeptide becomes protein

DNA must be copied before cell division

double helix seperated

each strand used as template to synthesize new copy

• Interphase-what a cell is in most of the time
• the nucleus is visible

Prophase-the centrioles move apart and spindle fibers are formed.

Metaphase-chromosomes are lined up at the equator

Anaphase-the centromeres split to opposite polls

Telephase- cell division nearly complete

necrosis- pathological cell death(i.e. disease)

• apoptosis- homeostatic cell death
• -cells die off in controlled fashion that does not damage adjacent cells

-signals received by target cell activate specific enzymes(caspases) which fragment DNA and disassemble organelles

• all chemical reactions occuring in a living organism
• -breakdownn of some substances

-build up of other substances

-requires enzymes to catalyze reactions