AP Biology - Unit 2 Review

General Information

Bacteria and archaea are ___________ organisms.

prokaryotic

Animals, plants, fungi, and protists are __________ organisms.

eukaryotic

_____________ have a nucleus and membrane-bound organelles.

eukaryotes

Instead of a nucleus, prokaryotes have a _________ region where the main chromosome is located.

nucleoid

__________ are small circular pieces of DNA separate from the main chromosome.

plasmids

Both prokaryotes and eukaryotes have what 4 things?

1. ribosomes

2. DNA

3. plasma membrane

4. cytoplasm

Protein synthesis occurs in the __________.

ribosome

The cell wall of bacteria is made up of _____________.

peptidoglycan

The cell wall of plants is made up of ____________.

cellulose

The cell wall of fungi is made up of ____________.

chitin

The ____________ provides structural support and prevents the cell from bursting due to water entering.

cell wall

The __________ in eukaryotes contains DNA.

nucleus

The _____________ is the site of cellular respiration.

mitochondria

The ____________ synthesizes and folds proteins that are generally for the cell membrane, organelles, or outside the cell.

rough endoplasmic reticulum

The ____________ synthesizes lipids and stores calcium.

smooth endoplasmic reticulum

The _____________ is responsible for modifying and packaging proteins and lipids for shipment.

Golgi apparatus

______________ break down cell parts and macromolecules.

Lysosomes

The nuclear envelope is a _________ membrane.

double

The ___________ produces and assembles ribosomes.

nucleolus

Ribosomes can be found free in the cytoplasm or attached to the ___________.

rough ER

A ___________ is a small membrane-bound compartment that transports materials around the cell.

vesicle

Lysosomes use __________ enzymes that can only activate in an acidic (low pH) environment.

hydrolytic

____________ are membrane-bound storage compartments for water, ions, nutrients, waste, and other substances.

vacuoles

The central vacuole in plants helps maintain ________ pressure.

turgor

The folds of the inner membrane in mitochondria are called ________, which increases surface area.

cristae

_____________ are the sites of photosynthesis.

chloroplasts

_____________ and ___________ both have double membranes, their own DNA, and their own ribosomes.

mitochondria and chloroplasts

The ______________ is an internal network of protein fibers that helps with cell shape, movement, and cell division.

cytoskeleton

_________ and _________ help cells move or move substances across the cell surface.

cilia and flagella

The ____________ separates the cell’s internal environment from its external environment and is selectively permeable.

plasma membrane

Describe the endomembrane system:

DNA → mRNA → ribosome → rough ER → vesicle → Golgi body → vesicle → plasma membrane → outside cell

By increasing _______________, the cristae allows for more sites for ATP-producing reactions in the mitochondria.

surface area

Surface area is important because cells____________________ with their environment.

constantly exchange materials

Cells want a ______ surface area-to-volume ratio.

high

As a cell gets larger, the surface area-to-volume ratio __________.

decreases

Cells tend to remain _____ because a high SA:V allows efficient exchange with the environment.

small

Cells can increase surface area by developing ______________.

specialized structures

____________ are specialized structures in the lungs that provide a large amount of surface area for gas exchange.

alveoli

The small intestine has __________ to increase surface area for absorbing nutrients.

microvilli

In addition to having a higher SA:V; in a small cell, molecules have to travel a _______ distance.

shorter

___________ increases faster than surface area.

volume

Phospholipids are __________, meaning they have both polar and nonpolar sides.

amphipathic

The head of a phospholipid is _____________.

polar, hydrophilic

The tail of a phospholipid is ___________.

nonpolar, hydrophobic

Water is found inside and outside cells, so phospholipids arrange in a __________.

bilayer

The plasma membrane is considered a ______ because phospholipids and proteins can move laterally.

fluid

The plasma membrane is also considered a __________ because it contains many different components mixed together.

mosaic

The plasma membrane is semi-permeable to maintain __________ by blocking harmful toxins from entering and keeping essential nutrients inside.

homeostasis

____________ create a passageway through the membrane.

channel proteins

_____________ bind to a substance and change shape to move it across the membrane.

carrier proteins

_____________ receive signals from outside the cell.

receptor proteins

__________ proteins act as enzymes and catalyze chemical reactions.

enzymatic

___________ membrane proteins are embedded with the membrane and can extend across the bilayer (transmembrane).

integral

____________ membrane proteins only attach to the surface of the membrane.

peripheral

_____________ is located between phospholipids and helps regulate membrane fluidity.

cholesterol

When temperatures get _____, phospholipids tend to pack together and cholesterol prevents them from becoming too rigid.

low

When temperatures get ______, phospholipids move around more and cholesterol prevents the membrane from becoming too fluid.

high

Cholesterol helps stabilize membrane fluidity across _________ changes.

temperature

The __________ fatty acid tails of phospholipids also prevent them from packing tightly because of the double bond, which creates a kink.

unsaturated

____________ and __________ help with cell recognition and cell-to-cell communication.

glycoproteins and glycolipids

Small, ________ molecules can cross the phospholipid bilayer easily, such as O2 and CO2.

nonpolar

Large, __________ molecules and ions have difficulty crossing the hydrophobic interior of the bilayer (which repels them), such as Na+, K+, and glucose.

polar

Large, polar molecules or ions need protein ______ or ______ to cross the membrane.

channels or carriers

In a concentration gradient, the movement of substances is from ____ to _____.

high to low

_________ is the net movement of particles from an area of higher concentration to an area of lower concentration.

diffusion

Equilibrium does NOT mean molecules stop moving; instead, it means there is no __________ in one direction.

net movement

____________ are membrane proteins that allow water to cross the membrane rapidly, and are abundant in kidney and plant cells.

aquaporins

Factors that affect membrane permeability include:

1. size

2. polarity

3. charge

4. lipid solubility

In __________ transport, no cellular energy is required.

passive

Passive transport involves moving substances down their ______________.

concentration gradient

__________ transport requires energy to move substances against a concentration gradient.

active

_______________ occurs when a substance moves directly through the phospholipid bilayer, like O2 and CO2.

simple diffusion

_______________ occurs when substances use proteins to cross the membrane down a concentration gradient.

facilitated diffusion

Channel proteins create a ________ passageway through the membrane, such as ion channels and aquaporins.

hydrophilic

__________ is the diffusion of WATER across a selectively permeable membrane.

osmosis

Water moves toward the side with _____ solute.

more

Transport proteins are ________. For example, aquaporins → water, glucose transporters → glucose.

specific

Transport proteins have a ______ number of binding sites or channels.

limited

If the concentration of substances becomes extremely high, transport proteins can become __________, which may appear as a plateau when graphing diffusion rate.

saturated

A ____________ is a membrane protein that uses energy to move substances against their concentration gradient.

protein pump

Protein pumps require _________ to work.

energy/ATP

In the ____________ pump, 3 Na+ moves out of the cell, and 2 K+ moves into the cell; both are being moved against their concentration gradients.

sodium-potassium

The sodium-potassium pump is important for maintaining the ___________ gradient needed for nerve signaling, muscle contraction, etc.

electrochemical

The sodium-potassium pump is an example of ________ active transport.

primary

__________ active transport uses energy stored in an electrochemical gradient to transport substances.

secondary

__________ involves two substances moving together, either in the same or opposite direction.

cotransport

____________ is when the cell membrane folds inward and surrounds material entering the cell.

endocytosis

____________ is a specific type of endocytosis in which the cell takes in large particles.

phagocytosis

____________ is a specific type of endocytosis in which the cell takes in extracellular fluid or dissolved substances.

pinocytosis

_____________ endocytosis relies on receptors on the cell membrane to recognize specific molecules.

receptor-mediated

___________ moves material out of the cell via a vesicle fusing with the plasma membrane, such as hormones, digestive enzymes, and waste products.

exocytosis

Both endocytosis and exocytosis are forms of __________ transport.

active

Bulk transport needs ______ because it physically involves reshaping the cell membrane.

energy

Water will move from a _________ water potential to a ________ water potential.

high → low

_____________ describes how a solution affects the movement of water across a selectively permeable membrane.

tonicity

___________ means more solute.

hypertonic

If a solution is hypertonic to a cell, water will move ______________.

out of the cell

___________ means less solute.

hypotonic

If a solution is hypotonic to a cell, water will move __________.

into the cell

__________ means both solutions have the same solute concentration and there is no net movement of water.

isotonic