CELLS - The cell is the smallest living thing.It is the lowest level of organization to have all the characteristics of life.

In the biotic world, there are two categories of cells:

 

PROKARYOTE EUKARYOTE

PRO = before            EU = true

KARYON = nucleus KARYON = nucleus


 

cell structures:

cell membrane [PLASMA MEMBRANE] = phospholipid bilayer

proteins

 

cytoplasm = fluid medium inside cell 

site of chemical reactions

 

cytoskeleton = part of cytoplasm - found in some eukaryotic cells

protein framework

actin filaments

intermediate filaments

microtubule

 

centriole = microtubule-triplet arrangement ---anchor for cilia & flagella

 

Cilia & flagella = extension(s) of cell membrane

used for movement

 

nucleus = contains genetic material

largest organelle - usually centrally located 

nuclear membrane - double layered

 

nucleolus = rRNA-----> ribosomes synthesized

 

ribosome = made up of rRNA & bound by protein complex

protein synthesis

 

endoplasmic reticulum = endo = within cytoplasm

reticulum = little net

smooth endoplasmic reticulum[ SER] 

rough endoplasmic reticulum [ RER]

SER = makes lipids & / or carbohydrates

RER = makes proteins

 

Golgi complex ='warehouse' of cell

modifies proteins with carbohydrates or phosphate groups

 

MUCUS production

lysosome = vesicle with hydrolytic enzymes

 

mitochondria = 'powerhouse' of cell

oxidative metabolism occurs to make ATP

C6H12O+O2------------>CO2+H2O+energy [ATP] 

 

TRANSPORT THROUGH CELL MEMBRANES


 

PASSIVE TRANSPORT - no energy required

osmosis- water movement across membranes

diffusion - molecular movement across membranes

 

CONCENTRATION GRADIENT- movement from a higher concentration to a lower concentration to achieve equilibrium

 

ACTIVE TRANSPORT - energy is required

phagocytosis - phagein = to eat

pinocytosis - pinein = to drink

endocytosis 

exocytosis

 

transport channels- 2 types of pumps

sodium - potassium pump- keep sodium out and potassium in

uses 1/3of cell's energy

proton pump

 

CELL DIVISION

CELL CYCLE or CYCLES -G1 = cell grows in size and cellular organelles increase in number

S = replication of DNA

G2 = various metabolic events occur to prepare for mitosis

M = mitosis

human fibroblasts -G1 =6.3 hours

S =7.0 hours

G2 =2.0 hours

M =0.7 hours

16 hours

EUKAROYOTE DIVISION- DNA is copied(S stage)

4 phases of mitosisprophase, metaphase, anaphase, telophase

cytokinesis