AP Bio Unit 2

Define cell theory

1. All living things are made of one or more cells

2.Cells are the basic unit of structure and function in an organism

3.Cells only come from the reproduction of other cells

Define a Prokaryotic cell

Unicellular organism that lacks a nucleus and has no membrane-bound organelles

Define a Eukaryotic cell

Multicellular organism that has a nucleus and membrane-bound organelles

Cell membrane

Cell's outer boundary that allows nutrients and wastes in and out of the cell

Selective Permeability

Only some materials are allowed either in or out of the cell

What is the phospholipid bilayer

The phospholipid bilayer is a foundational structure of cell membranes, composed of two layers of phospholipids with hydrophilic/polar heads and hydrophobic/nonpolar tails. This arrangement provides a semi-permeable barrier that regulates the movement of substances in and out of the cell.

Cytoplasm vs. cytosol

Cytosol is the aqueous component of the cytoplasm, containing dissolved ions and molecules, while cytoplasm includes all contents within the cell membrane

Nucleus

Directs the cell’s activities and contains DNA (control center)

Ribosomes

Makes proteins by joining together amino acids (assembly line)

Nucleolus

Sperichal are inside of the nuclues that makes RNA and ribosome parts

What is in a Lipid Bilayer

HydroPHILIC head (polar)

HydroPHOBIC tail (nonpolar)

Vesicle

Small spherical membrane sac that transports proteins and other materials

Endomembrane System

regulates protein movement and performs metabolic functions

Smooth ER vs. Rough ER

Smooth= NO ribosomes, on surface, synthesizes lipids, detox, etc. (oil workshop)

Rough = Ribosomes on surface and packages proteins (protein packers)

Golgi Apparatus

(CIS/TRANS face)

Post office! Packages different molecules into vesicles. Also assists the E.R.

CIS face= receiving side of the Golgi and is near the ER

TRANS face= shipping side of the Golgi and modifies proteins for the vesicle

Lysosomes

Digestion of macromolecules (garbage disposal)

Types of Vacuoles

Food= Where we store food

Contractile= Pushing out water

Central= Where plants store water

Mitochondria

Produces energy/ATP

Chloroplast

Site of photosynthesis in plants

Cell Wall

Protects plants and maintain shape (composed of cellulose)

Endosymbiosis theory

How first eukaryotic cell came into existence. Consumption of prokaryotes by other prokaryotes forming a eukaryote

Peroxisome

Break down fatty acids and detox alcohol (detoxifiers and cleaners)

Cytoskeleton

Network of protein fibers

Types of transmembrane proteins

1) Channel proteins= allows specific molecules to pass across the cell membrane

2) Carrier proteins= binds to a molecules CHANGES shape, and moves the molecule

Function of glycolipids and glycoproteins

Both are attached to carb chains for cell-to-cell recognition and for membrane stability

Osmosis

Diffusion of H2O

Diffusion

High to low movemnt, ATP is NOT used, Directly through lipid bilayer/membrane, Small/non-polar molecules. Moves molecules DOWN their concentration gradient

Facilitated diffusion

High to low movement, ATP is NOT used, Through proteins, large/polar molecules

Active Transport

REQUIRES ATP and proteins transport substances AGAINST their concentration gradient (low to high)

Electrogenic Pumps and types

Electrogenic Pumps generate voltage across membranes

Sodium-Potassium Pump= moves sodium ions out of the cell and potassium ions into the cell (ex= nerve transmission)

Proton Pump= Push protons across membrane (ex= mitochondria for ATP production)

Cotransport

Membrane protein enables “downhill” diffusion of one solute to drive “uphill” transport of other

Bulk Transport and types

Bulk Transport is ACTIVE transport of large molecules, polysaccharides, and proteins

Endocytosis= Taking in macromolecules by engulfing them with its plasma membrane to form internal vesicles

Exocytosis= Vesicles fuse with the plasma membrane, secrete contents out of cell

Types of Endocytosis?

Phagocytosis= Cell takes in large particles of solids “cell eating”

Pinocytosis= Cell takes in fluid/dissolved molecules “cell drinking”

Receptor-Mediated Endocytosis= Ligands bind to specific receptor on cell surface

Aquaporins

Channel protein that allows passage of H2O

Osmotic pressure

Pressure applied to a cell’s solution to stop water from moving into the membrane by osmosis. Directly affects cell shape, stability, and survival

Water potential

Where water moves spontaneously from high water potential (less negative) to low water potential (more negative)

Solute potential

The measure of the tendency of water to move by osmosis due to the presence of solute particles, influencing overall water potential

Plasmolysis

When a plant cell is placed in a hypertonic solution and loses water, causing it to shrink

Flaccid

Plant is no longer firm and becomes limp because it has lost its tuggor pressure

Turgid

Normal state for plant cells= stiff and upright

Cytolysis

The process where a cell bursts due to excessive intake of water when placed in a hypotonic solution, leading to swelling and rupture

Osmolarity

A measure of solute concentration in a solution, expressed as the number of osmoles of solute per liter of solution

What is the Surface Area to Volume Ratio impact on cell size

Higher SA:V ratio in smaller cells and enables faster exchange of nutrients, thermal energy, and waste with the environment

What are cellular strategies to maximize surface area

Membrane infoldings like microvilli, root hairs, mitochondrial cristae, and thylakoid grana stacks

What is the role of cholesterol in animal membranes

Acts as fluidity buffer restrains phospholipid movement at high temperatures and prevents tight packing at low temps