AP Bio Unit 2 Test

Cell Theory

Living matter is composed of one or more cells; The cell is the structural and functional unit of life; All cells are created from previous cells

Organelle

Formed body in a cell with a specialized function (small organ); Important in the organizational structure of cells;

Their Function: a way to form compartments in cells to separate chemical reactions

Nucleus Function

Contains the genetic instructions to make proteins & DNA; Protects DNA; Most conspicuous organelle;

Nucleus Structure

Has 4 components: Nuclear Membrane, Nuclear Pores, Nucleolus, & Chromatin

Nuclear Membrane

Double membrane; Inner membrane supported by a protein matrix to provide shape

Nuclear Pores

Allows things in & out of the nucleus (on the outer membrane); Ex: mRNA during transcription

Nucleolus

Dark staining area inside the nucleus (0-4 per nucleus); Stores ribosomes

Chromatin

DNA and Protein in a “loose” format; Will form the cell’s chromosomes (Chrom- = Colored; -atin = Threads)

Ribosomes Function

Protein synthesis;

Ribosomes Structure

2 subunits made of protein and rRNA *No Membrane*

Ribosomes: Free in Cytoplasm

Make proteins for use in the cell

Ribosomes: Membrane Bound

Make proteins that are exported from the cell (on rough ER)

Endoplasmic Reticulum Structure

Folded sheets of membrane tubes; continues the nuclear membrane; makes up ½ of the total membrane in cells

Smooth Endoplasmic Reticulum Function

No Ribosomes; Used for: lipid synthesis, carbohydrate storage, and detoxification of poisons

Rough Endoplasmic Reticulum Function

Has Ribosomes; used for ribosomes to make proteins; BOTH provide intercellular transport through vesicles

Golgi Apparatus Structure

A parallel array of a flattened cisternae (looks like stacks of pancakes); 3 - 20 per cell; likely an outgrowth of the ER system

Golgi Apparatus Function

“The Editor”; Processing, Distribution, and Transportation of Proteins

Golgi Apparatus: Processing

Checks for correct folding and chemical modifications of newly made proteins

Golgi Apparatus: Distribution

Packaging of ER products for transport

Golgi Apparatus: Transport (Golgi Vesicles)

Small sacs of membranes that bud off of the Golgi body; Transportation vehicle of modified ER products

Lysosomes Structure

Single membrane sacs (made from Golgi Apparatus)

Lysosomes Function

Breakdown/Degrades cellular materials; contains hydrolytic enzymes for fats, proteins, polysaccharides, and nucleic acids

Lysosomes (cont.)

Important in cell death; missing enzymes may cause various genetic enzyme diseases

Vacuoles Structure

Single membrane; Varies in size and shape

Vacuoles Function: Animal Cell

Storage/Release of macromolecules; waste storage

Vacuoles Function: Plant Cell

Water retention/turgor pressure; Can also store pigments

Protist Contractile Vacuole

Pump out access water

Protist Food Vacuole

Stores newly ingested food until lysosomes can digest it

Peroxisomes Structure

Single membrane sacs

Peroxisomes Function

Specialized enzymes for specific reactions; use up/break down hydrogen peroxide; ONLY FOUND IN ANIMAL CELLS

Mitocondria Structure

Has 2 membranes; inner membrane has more surface area than outer membrane

Mitochondria Matrix

Inner space of organelle

Mitochondria Intermembrane Space

Area between membranes

Mitochondria Inner Membrane

Folded into cristae; amount of folding depends on cell activity; contains many enzymes; ATP generated in mitochondria

Mitochondria Function

Cellular Respiration- the release of energy (glucose) from food; Makes energy (ATP) for cell

Mitochondria (cont.)

Have ribosomes; contain their own DNA; can reproduce themselves; may have been independent cells at one time

Chloroplast Structure

Two outer membranes; complex inner membrane; fluid-like stroma is around the internal membranes

Chloroplast Inner Membrane

Thylakoid Membrane; arranged into flattened sacs called Thylakoids; some regions stacked into layers called grana; contains the green pigment chlorophyll

Chloroplast Function

Photosynthesis- the use of light energy to make food (glucose); ONLY FOUND IN PLANT CELLS

Chloroplast (cont.)

Contains ribosomes; contain DNA; can reproduce themselves; may have been independent cells at one time

Cytoskeleton Structure

Network of rods and filaments in the cytoplasm; very dynamic- changing in composition and shape frequently

Cytoskeleton Functions

Cell structure and shape; cell movement; cell division (helps build cell walls and move chromosomes apart)

Cytoskeleton Components

Microtubules: Bone-like; most rigid; thick

Microfilaments: cartilage-like; bendable; easier to break; thinner

Cell Wall Structure

Non-living jacket that surrounds some cells (Found in: plants, prokaryotes, fungi, and some protists)

Cell Wall Function

Cell’s exoskeleton for support and protection

Extracellular Matrix

“Fuzzy Coat” on animal cells; helps to glue cells together; made of glycoproteins and collagen; involved with cell behavior and communication (like velcro)

Prokaryote

Single-celled organism; lacks a nucleus and membrane-bound structures

Eukaryote

Multi-celled organism; have a nucleus and other membrane bound structures

Characteristics of both Prokaryotic and Eukaryotic cells

Both have: membrane, cytosol, ribosomes (differ in size)

Protist

Single-celled eukaryotic organism

Prokaryote: Capsule

Sticky outer layer

Prokaryote: Cell Wall

Protects/maintains shape

Prokaryote: Plasma Membrane

Controls movement of materials in/out of the cell

Prokaryote: Pilli

Used for attachment; joins bacteria together for transfer of DNA

Prokaryote: Flagella

Allows for cell motility

Prokaryote: Ribosomes

Protein synthesis

Prokaryote: Nucleoid

Contains DNA

Why are cells so small?

Surface area > volume; the cell needs to be large enough to perform functions correctly, but small enough to control materials in/out of the cell

Membrane Composition

Phospholipids, Proteins, Cholesterol (steroids), and Glycoproteins/Glycolipids (Ogliosaccharides)

Phospholipids

Makes up phospholipid bilayer of cell membrane; hydrophilic head; hydrophobic tail

Fluid Mosaic Model

The way phospholipids and proteins behave in a membrane

Fluid Mosaic Model: Fluid

Refers the way the phospholipid bilayer molecules are not bonded together, so they are free to shift; must remain fluid for membranes to function

Fluid Mosaic Model: Mosaic

Proteins float in a sea of phospholipids; proteins form a collage or mosaic pattern that shifts over time

Protein functions in membrane

Transport, Enzymatic Activity, Receptor sites for signals, Cell adhesion, cell to cell recognition, Attachment to cytoskeleton

Integral Proteins

Inserted into the phospholipid bilayer

Peripheral Proteins

Are attached to the membrane surface (does not go all the way through the membrane)

How do integral proteins stick inside the membrane?

Solubility of their amino acids; Non-polar proteins will be in hydrophobic areas

Bifacial Membranes

Inside layer of membrane is different from outer layer; proteins have specific orientations; carbohydrates are only found on the outer surface

Membrane Carbohydrates

Branched Ogliosaccharides form glycoproteins and glycophospholipids on the external surface; Function: Cell-to-cell recognition

Membrane Cholesterol

Keeps membranes at the right fluidity level (not too flimsy, not too rigid)

Passive Transport

Movement across the membrane that does not require cellular energy

Diffusion

Net movement of atoms, ions, or molecules down a concentration gradient; Imports materials in, and exports waste out

Down (With) Concentration Gradient

High Concentration → Low Concentration

Equilibrium

When the concentration is equal on both sides; no net movement of materials; (O₂ and CO₂ can easily pass through)

Factors that effect diffusion

Concentration, Temperature, Pressure, Particle Size, Mixing

Osmosis

Diffusion of Water; water moving from an area of high concentration to low concentration

Tonicity

The concentration of water in the environment relative to a cell

Isotonic

Cell and Water are equal in solute concentration; no net movement of H₂O in or out of the cell

Hypotonic

Cell’s water is lower than the outside water (more solutes); water moves into the cell; cell swells, may burst or become turgid

Hypertonic

Cell’s water is higher than the outside water (less solutes); water moves out of the cell; cell shrinks or plasmolysis occurs

Facilitated Diffusion

Requires transport protein that helps materials through cell membrane; no energy required

Aquaporins

Newly found channels for osmosis

Active Transport

Movement across membranes that does require cellular energy

Carrier Mediated Transport

General term for the active transport of materials into cells against the concentration gradient

Ex: Na+ - K+ pumps (Na out of cell, K into cell), H+ pumps (H out of cell)

Up (against) the Concentration Gradient

Low Concentration → High Concentration

Cotransport

Movement of H+ ions that allows other materials to be transported into the cell as the H+ diffuses back across the cell membrane

Ex: Sucrose transport

Exocytosis

Moves bulk material out of cells

Ex: Secretion of enzymes

Endocytosis

Moves bulk material into the cell

Types: Pinocytosis (liquids); Phagocytosis (solids)

Endosymbiotic Theory

The theory that explains the creation of Eukaryotic cells; States that the mitochondria and chloroplast in eukaryotic cells were once aerobic bacteria (prokaryote) that were ingested by a larger anaerobic bacteria (prokaryote), creating the first eukaryotic cell

Regulated Cell Death

Apoptosis; Caused by Lysosomes purposefully breaking open and spreading their enzymes around the cell (These enzymes break down cell materials and cause cell death when unconfined)