General Biology Unit 7

Cells and microscopes etc

Three principles of Cell Theory

Three principles of Cell Theory

all living organisms have one or more cells. cells are the basic unit of structure and organization of all living organisms, and cells arise only from pre existing cells

Plasma membrane

A special boundary that helps control what enters and exits the cell

Each cell has…

genetic material

Cells generate energy by…

breaking down molecules

What are the two types of cells?

Eukaryote and prokaryote

Prokaryotic cells

cells without a nucleus or other membrane-bound organelles

Differences of Eukaryotes and Prokaryotes

prokaryotes are smaller and have no membrane-bound organelles

Eukaryotic cells

cells that contain a nucleus and other organelles

Organelles

specialized structures that perform specific cell functions

Nucleus

the distinct central organelle where the genetic information is stored

Homeostasis

the process of maintaining balance in an organisms internal environment

What structure is responsible for homeostasis

the plasma membrane

Selective permeability

the restriction of only allowing certain things in and out of the plasma membrane

Phospholipid bilayer

two layers of phospholipids that are arranged to allow the membrane to exist in a watery environment

How is the phospholipid bilayer constructed?

the phospholipid bilayer has polar heads facing outside and nonpolar tails facing inside, allowing the membrane to keep the internal and external components seperate

What does the plasma membrane contain?

cholesterol, proteins, and carbohydrates

Transportation proteins

proteins that move substances and wastes through the membrane

Cholesterol

precents the fatty acid tails from sticking together and contributes to the fluidity of the plasma membrane

Carbohydrates

carbohydrates define the cells characteristics and identify chemical signals

Cytoskeleton

supporting network of long, thin protein fibers that form a frame for the cell and provide an anchor for the organelles

Features plant cells have that animal cells dont

chloroplasts, vacuoles, and cell walls

Protein synthesis

a process that begins in the nucleus where RNA and ribosomes leave and produce a protein on the ER which are then sent to the Golgi for packaging where their packages are sent to other organelles

Diffusion

the net movement of particles from an area of high concentration to an area of low concentration

Facilitated Diffusion

uses transport proteins to move ions and small molecules across the plasma membrane

Diffusion and facilitated diffusion

types of passive transport

Passive Transport

type of transport that do not require energy

Osmosis

the diffusion of water across a selectively permeable membrane

Isotonic solutions

a solution that has the same concentration of water and solutes as the cytoplasm of the cell

Hypotonic solution

a solution that has a lower concentration of solutes than the cytoplasm of the cell

Hypertonic solution

a solution that has a higher concentration of solutes than the cytoplasm of the cell

Active transport

transport that requires energy because it goes against the concentration gradient

NA/K ATPase pumps

found in the membrane of animal cells that maintain levels of sodium and potassium inside/outside the cell

Large molecules

molecules that need to move against the concentration gradient into the cell

Coupled transport

a process where sugars can pair with Na+ ions and enter the cell through a membrane protein called a coupled channel to save energy

Endocytosis

the processes by which a cell surrounds an object in the outside environment in a portion of the plasma membrane (going in)

exocytosis

the exertion of materials in the plasma membrane (going out)