Bushman AP Bio Summer Assignment Test

What surrounds a cell?

The cell membrane (plasma membrane).

What is the cell membrane made of?

Phospholipid bilayer.

What does 'bilayer' mean?

Two layers of phospholipids.

Name the parts of a phospholipid.

Polar head, glycerol backbone, fatty acid chains.

What type of molecules are hydrophilic?

Molecules that are attracted to water.

What type of molecules are hydrophobic?

Molecules that avoid water.

What is diffusion?

Movement of particles from high to low concentration.

What is osmosis?

Diffusion of water through a cell membrane.

What is facilitated diffusion?

Molecules moving through a protein channel without energy.

What is active transport?

Molecules moving from low to high concentration using energy.

What are endocytosis and exocytosis?

Endocytosis brings things in; exocytosis pushes things out.

What is the nucleus?

The control center of the cell; stores DNA.

What are nucleoli?

Structures in the nucleus that make ribosomes.

What do ribosomes do?

Make proteins.

Difference between rough and smooth ER?

Rough ER makes glycoproteins; smooth ER makes lipids and detoxifies.

Function of the Golgi apparatus?

Modifies, sorts, and ships proteins.

What do lysosomes do?

Break down food, debris, and invaders.

What do peroxisomes do?

Break down unwanted cell parts using H₂O₂.

Function of mitochondria?

Produce ATP (energy) via cellular respiration.

Function of chloroplasts?

Conduct photosynthesis in plant cells.

What are microtubules?

Tubulin proteins for support, motility, and spindle formation.

What are microfilaments?

Actin proteins; involved in cell motility.

What are intermediate fibers?

Provide structural support.

What do centrioles do?

Organize microtubules for cell division.

What are basal bodies?

Organize cilia and flagella.

What is a desmosome?

Protein anchor between animal cells.

What is a tight junction?

Seals cells together; prevents material from passing between cells.

What is a gap junction?

Protein tunnel allowing ions/small molecules to pass between cells.

What is a plasmodesmata?

Plant cell channel connecting cytoplasm of neighboring cells.

State the cell theory.

All life is made of cells; cells come from pre-existing cells; cell is smallest unit of life.

Difference between prokaryotes and eukaryotes?

Prokaryotes: no nucleus, 70s ribosomes. Eukaryotes: nucleus, 80s ribosomes.

What are the three domains of life?

Bacteria, Archaea, Eukarya.

What does a light microscope show?

Live or prepared cells ≥200 nm.

Difference between TEM and SEM?

TEM: thin 2D slices of dead cells. SEM: 3D surface images of dead cells.

Why is water a good solvent?

It's polar; dissolves ionic and polar substances.

Why does ice float?

Solid water is less dense than liquid water.

What is cohesion?

Water molecules stick together.

What is adhesion?

Water sticks to other surfaces.

What is capillary action?

Water rises in narrow tubes due to cohesion and adhesion.

What is specific heat capacity?

Energy needed to raise 1g of substance by 1°C.

What is a monomer?

A single unit of an organic molecule.

What is a polymer?

A chain of monomers.

Examples of monosaccharides?

Glucose, fructose.

Examples of disaccharides?

Sucrose, lactose, maltose.

Examples of polysaccharides?

Starch, glycogen, cellulose, chitin.

Structure of triglycerides?

1 glycerol + 3 fatty acids.

Structure of phospholipids?

1 glycerol + 2 fatty acids + phosphate group.

What are steroids?

Lipids with 4 carbon rings (cholesterol, hormones).

What are proteins made of?

Amino acids linked by peptide bonds.

Name protein structure levels.

Primary, secondary, tertiary, quaternary.

What is an enzyme?

A protein that speeds up reactions.

What is a substrate?

The molecule an enzyme acts on.

Explain induced-fit.

The process by which an enzyme changes shape to better fit the substrate.

Induced-fit

Enzyme changes shape to fit substrate.

Denaturing enzymes

High/low temperature or extreme pH.

Cofactor

Nonprotein helper for enzymes.

Coenzyme

Organic cofactor (often vitamins).

ATP

Energy molecule; adenine + 3 phosphates.

Feedback inhibition

End product shuts down enzyme activity.

Competitive inhibition

Binds active site.

Noncompetitive inhibition

Binds elsewhere, changes enzyme shape.

Cooperativity

Binding of one substrate increases enzyme's affinity for more substrates.

Cell membrane function

Controls what enters and leaves the cell and protects it.

Hydrophilic part of phospholipid

The polar head.

Hydrophobic part of phospholipid

The fatty acid tails.

Fluid mosaic model

Because proteins float in or on the fluid lipid bilayer like tiles in a mosaic.

Molecules passing through lipid bilayer

Small, nonpolar molecules like O₂ and CO₂.

Facilitated diffusion vs active transport

Facilitated diffusion does not use energy; active transport uses ATP.

Chromatin

Thread-like DNA and proteins inside the nucleus.

Difference between DNA, chromatin, and chromosomes

DNA is the genetic material; chromatin is uncondensed DNA; chromosomes are condensed DNA during cell division.

Ribosome subunits

Made in the nucleolus.

Ribosome assembly

Subunits are made in the nucleus, then assembled in the cytoplasm.

Function of vesicles

Transport materials within the cell.

Golgi apparatus interaction with ER

Receives proteins/lipids from ER, modifies them, and ships them to their destination.

Plant cells and lysosomes

They often use vacuoles for digestion instead.

Peroxisomes

Break down H₂O₂, a toxic byproduct, into water and oxygen.

9+2 arrangement

Microtubule arrangement in cilia and flagella: 9 doublets around 2 central microtubules.

Flagella vs cilia movement

Flagella: whip-like motion. Cilia: oar-like, coordinated beating.

Basal bodies vs centrioles

Basal bodies organize cilia/flagella; centrioles organize spindle fibers in cell division.

Main role of the cytoskeleton

Support, shape, and movement of the cell.

Gap junctions and plasmodesmata

Gap junctions: animal cells exchange ions/molecules. Plasmodesmata: plant cells exchange cytoplasm and molecules.

Activation energy

Energy needed to start a chemical reaction.

Substrate-specific

Each enzyme only binds certain substrates.

Apoenzyme

The protein part of an enzyme without its cofactor.

Holoenzyme

Apoenzyme + cofactor (fully functional enzyme).

Role of vitamins in enzyme function

Vitamins often act as coenzymes.

Competitive inhibitor

Mimics the substrate and blocks the active site.

Noncompetitive inhibitor

Binds elsewhere, changes enzyme shape, preventing activity.

Allosteric activator

Binds allosteric site, changes enzyme to active form.

Feedback inhibition regulation

End product binds to enzyme, stopping further production.