The building blocks of the human body.
Surrounds the nucleus & contains a fluid cytosol & intracellular structures called organelles.
Fluid that surrounds the nucleus. Differs in composition from the extracellular fluid that surrounds most cells of the body.
Net movement of material from an area where concentration is relatively high to an area where its concentration is lower. It occurs until the concentration gradient is eliminated.
- Packaging of extracellular materials in a vesicle at the cell surface for import into the cell.
- 1) receptor mediated (active process)
- 2) pinocytosis ("cell-drinking")
- 3) phagocytosis ("cell-eating"
Functional reverse of endocytosis.
Endoplasmic Reticulum (ER)
Network of intracellular membranes.
Rough Endoplasmic Reticulum (RER)
Contains ribosomes & is involved in protein synthesis.
Smooth Endoplasmic Reticulum (SER)
Does not contain ribosomes; it is involved in lipid & carbohydrate synthesis.
A functional unit of heredity, & each gene consists of all the triplets needed to produce a specific protein.
Its DNA sores information used by the nucleus to direct the synthesis of specific proteins.
Forms secretory vesicles & new membrane components, & it packages lyosomes. Secretions are discharged from the cell by exocytosis.
Responsible for 95% of the ATP production within a typical cell. The matrix, or fluid contents of a mitochondrion, lies inside cristae, or folds of an inner mitochondrial membrane.
A membranous sac in the cytoplasm of a cell.
Contains secretions that will be discharged from a cell.
Vesicles filled with digestive enzymes. Functions include ridding the cell of bacteria & debris.
Smaller than lysomes & carry a different group of enzymes. They arise from the growth & subdivision of existing peroxisomes.
Control center for cellular operations. Surrounded by a nuclear envelope, through which it communicates with the cytosol by way of nuclear pores.
The diffusion of water across a membrane in response to differences in concentration.
The force of movement of water across a membrane in osmosis.
"It is a form of endosytosis. "cell-eating" produces vesicles that contain solid objects.
Includes both transcription & translation.
Part of protein synthesis. It is the production of RNA from a single strand of DNA. It takes place within the nucleus.
The assembling of a protein by ribosomes, using the information carried by the RNA molecule. It takes place in the cytoplasm.
It is sensitive to a particular environmental change or stimulus.
Functions of Cell Membranes
- 1) physical isolation
- 2) Control of the exchange of materials
- 3) sensitivity
- 4) structural support
Cell Membrane (or Plasma Membrane) Contains...
- 1) lipids
- 2) proteins
- 3) & carbohydrates
- (Its major components, lipid molecules, form a phospholipid bilayer.)
Membrane proteins may function as...
1) receptors 2) channels 3) carriers 4) enzymes 5) anchors 6) identifiers
Hydrostatic pressure forces water across a membrane. If membrane pores are large enough, molecules of solute will be carried along with the water.
A type of carrier-mediated transport & requires the presence of carrier proteins in the membrane.
Active Transport Mechanism
Consumes ATP & are independent of concentration gradients. Some ion pumps are exchange pumps.
Material moves into or out of a cell in membranous sacs.
- Surrounded by lipid membranes that isolate them from the cytosol. Membranous organelles include:
- 1) endoplasmic reticulum
- 2) the nucleus
- 3) the Golgi appraratus
- 4) lysomes
- 5) mitochondria
- Always in contact with they cytosol.
- 1) cytoskeleton
- 2) microvilli
- 3) centrioles
- 4) cilia
- 5) flagella
- 6) proteasomes
- 7) ribosomes
- Gives the cytoplasm strength & flexibility. Main components:
- 1) microfilaments
- 2) intermediate filaments
- 3) microtubules
Small projections of the cell membrane that increase the surface area exposed to the extracellular enviroment.
Direct the movement of chromosomes during cell division.
Move a cell through surrounding fluid rather than moving fluid past a stationary cell.
Intracellular factory that manufactures proteins. 1) free ribosomes are in the cytoplasm 2) fixed ribosomes are attached to the endoplasmic reticulum.
Remove & break down damaged or abnormal proteins.