AP Biology Unit 2 Test

Ribosomes

comprise RNA (rRNA) and protein. ___ synthesize protein
according to mRNA sequence.

Endoplasmic Reticulum

occurs in two forms—smooth and rough.

Rough ER

compartmentalizes the cell.

Smooth ER

functions include detoxification and lipid synthesis.

Golgi

is a membrane-bound structure that consists of a series of flattened membrane sacs; Functions of the ___ include the correct folding and chemical modification of newly synthesized proteins and packaging for protein trafficking.

Mitochondria

have a double membrane. The outer membrane is smooth, but the inner membrane is highly convoluted, forming folds.

Lysosomes

membrane-enclosed sacs that contain hydrolytic enzymes.

Vacuole

membrane-bound sac that plays many and differing roles. In plants, a specialized large vacuole serves multiple functions.

Chloroplast

specialized organelles that are found in photosynthetic algae and plants. ___ have a double outer membrane.

Endoplasmic Reticulum

provides mechanical support, carries out protein synthesis on
membrane-bound ribosomes, and plays a role in intracellular transport.

Mitochondrial Double Membrane

membrane provides compartments for different metabolic reactions.

Lysosomes

contain hydrolytic enzymes, which are important in intracellular digestion, the recycling of a cell’s organic materials, and programmed cell death (apoptosis).

Vacuoles

have many roles, including storage and release of macromolecules and cellular waste products. In plants, it aids in retention of water for turgor pressure.

SA:V

affect the ability of a biological system to obtain necessary
resources, eliminate waste products, acquire or dissipate thermal energy, and otherwise exchange chemicals and energy with the environment.

higher

Smaller cells typically have a ___ surface area-to-volume ratio and more efficient exchange of materials with the environment.

more

Smaller cells typically have a higher surface area-to-volume ratio and ___ efficient exchange of materials with the environment.

decreases

As cells increase in volume, the relative surface area ___ and the demand for internal resources increases.

decreases

As organisms increase in size, their surface area-to-volume ratio ___, affecting properties like rate of heat exchange with
the environment.

hydrophilic

Phospholipids have both hydrophilic and
hydrophobic regions. The ___ phosphate regions of the phospholipids are oriented toward the aqueous external or
internal environments.

hydrophobic

Phospholipids have both hydrophilic and hydrophobic regions. The ___ fatty acid regions face each other within the interior of the membrane.

selective permeability

The structure of cell membranes results in ___.

Selective Permeability

___ is a direct consequence of membrane structure, as described by the fluid mosaic model.

small nonpolar molecules

___, including N2, O2, and
CO2, freely pass across the membrane

hydrophilic

___ substances, such as large polar molecules and ions, move across the membrane through embedded channel and transport proteins.

polar uncharged

___ molecules, including H2O, pass through the membrane in small amounts.

complex carbohydrates

Cell walls of plants, prokaryotes, and fungi are composed of ___

Passive transport

___ is the net movement of molecules from high concentration to low concentration without the direct input of metabolic energy.

High, low

Passive transport is the net movement of molecules from ___ concentration to ___ concentration without the direct input of
metabolic energy.

without

Passive transport is the net movement of molecules from high concentration to low concentration ___ the direct input of metabolic energy.

active transport

___ requires the direct input of energy to move molecules from regions of low concentration to regions of high concentration.

low, high

Active transport requires the direct input of energy to move molecules from regions of ___ concentration to regions of ___ concentration.

exocytosis

In ___, internal vesicles fuse with the plasma membrane and secrete large macromolecules out of the cell.

endocytosis

In ___, the cell takes in macromolecules and particulate matter by forming new vesicles derived from the plasma membrane.

aquaporins

In facilitated diffusion, large quantities of water pass through
___

Charged ions

In facilitated diffusion, ___ including Na+ and K+, require channel proteins to move through the membrane.

channel proteins

In facilitated diffusion, charged ions including Na+ and K+, require ___ to move through the membrane.

osmosis

Water moves by ___ from areas
of high water potential/low osmolarity/
low solute concentration to areas of low
water potential/high osmolarity/high
solute concentration.

High, low

Water moves by osmosis from areas of ___ water potential to areas of ___ water potential

low, high

Water moves by osmosis from areas of ___ osmolarity to areas of ___ osmolarity

low, high

Water moves by osmosis from areas of ___ solute concentration to areas ___ solute concentration.

Osmoregulation

___ maintains water balance and allows organisms to control their internal solute composition/water potential.

minimizing, increasing

Internal membranes facilitate cellular processes by ___ competing interactions and by ___ surface areas where reactions can occur.

endosymbiosis

Membrane-bound organelles evolved from once free-living prokaryotic cells via ___.

Active Transport

The movement of a substance across a cell membrane against its concentration gradient, mediated by specific transport proteins and requiring an expenditure of energy

Active Transport

the movement of materials through a cell membrane using energy

Amphiphatic

a molecule that has both hydrophobic and hydrophilic regions.

Apoptosis

A type of programmed cell death, which is brought about by activation of enzymes that break down many chemical components in the cell

Aquaporin

A channel protein in a cellular membrane that specifically facilitates osmosis

ATP

Adenine-containing nucleoside releases free energy when its phosphate bonds are hydrolyzed; drives endergonic reactions in cells

Barr

A dense object lying along the inside of the nuclear envelope in cells of female mammals; represents a highly condensed, inactivated X chromosome

Cell Wall

A protective layer external to the cell membrane in the cells of plants, prokaryotes, fungi, and some protists; important structural components include cellulose and peptidoglycan

Chlorophyll

Chloroplast

An organelle found in plants and photosynthetic protists that absorbs sunlight and uses it to drive the synthesis of organic compounds from carbon dioxide and water

Concentration Gradient

difference in concentration of a substance on two sides of a membrane

Cytoplasm/cytosol

a jellylike fluid inside the cell in which the organelles are suspended; region of the cell between the cell membrane and the nucleus

Diffusion

the random movement of a substance down its concentration gradient from a more concentrated to a less concentrated area.

Endocytosis

Cellular uptake of biological molecules and particulate matter via formation of vesicles from the plasma membrane

Endomembrane system

the collection of membranes inside and around a eukaryotic cell, related either through direct physical contact or by the transfer of membranous vesicles

Endoplasmic reticulum

an extensive membranous network in eukaryotic cells, continuous with the outer nuclear membrane and composed of ribosome-studded (rough) and ribosome-free (smooth) regions.

Endosymbiont Theory

the theory that mitochondria and plastids, including chloroplasts, originated as prokaryotic cells engulfed by an ancestral eukaryotic cell. The engulfed cell and its host cell then evolved into a single organism.

Eukaryote

a cell that contains a nucleus and membrane bound organelles

Facilitated Diffusion

The passage of molecules or ions down their electrochemical gradient across a biological membrane with the assistance of specific transmembrane transport proteins; requires no energy expenditure

Flaccid

limp. Lacking in stiffness or firmness, as in a plant cell in surroundings where there is no tendency for water to enter the cell

Fluid Mosaic Model

model of cell membrane structure, which envisions the membrane as a mosaic of protein molecules drifting laterally in a fluid bilayer of phospholipids.

Gated channels

protein channels in a cell membrane that opens or closes in response to a particular stimulus.

Glycolipid

a lipid with covalently attached carbohydrate(s).

Glycoprotein

a protein with one or more carbohydrates covalently attached to it.

Glycoproteins

proteins that have carbohydrates covalently attached to them (carbohydrate "flag" or name-tag; lock-key)

Golgi apparatus

stack of membranes in the cell that modifies, sorts, and packages proteins from the endoplasmic reticulum ("corrupt fedex")

Granum

a stack of membrane-bounded thylakoids in the chloroplast

Hydrophilic

having an affinity for water

Hypertonic

describes a solution whose solute concentration is higher than the solute concentration inside a cell (causes the cell to shrink/shrivel)

Integral Protein

a transmembrane protein with hydrophobic regions that completely spans the hydrophobic interior of the membrane

Ion channels

protein channels that allows a specific ion to flow across the membrane down its concentration gradient

Isotonic

describes a solution whose solute concentration is equal to the solute concentration inside a cell (causes no net change of water into or out of the cell)

Membrane Potential

the difference in electrical charge (voltage) across a cell's plasma membrane due to the differential distribution of ions.

Mitochondria

organelle in eukaryotic cells that serves as the site of cellular respiration; uses oxygen to break down organic molecules and synthesize ATP

Mitochondrial matrix

the compartment of the mitochondria enclosed by the inner membrane and containing enzymes and substrates for the citric acid cycle as well as ribosomes and DNA

Nuclear envelope

layer of two membranes that surrounds the nucleus of a cell

Nucleolus

organelle where ribosomes are made, synthesized and partially assembled, located in the nucleus

Organelle

any of several membrane-enclosed structures with specialized functions, suspended in the cytosol of eukaryotic cells

Osmoregulation

regulation of solute concentrations and water balance by a cell or organism

Osmosis

the diffusion of water across a selectively permeable membrane (from high to low)

Peripheral Protein

a protein loosely bound to the surface of a membrane and not embedded in the lipid bilayer

Phagocytosis

a type of endocytosis in which large particulate substances are taken up by a cell

Plasmolysis

when the cytoplasm shrivels and the plasma membrane pulls away from the cell wall; occurs in plant cells when the cell loses water to a hypertonic environment.

Pressure Potential

A component of water potential that consists of the physical pressure on a solution, which can be positive, negative, or zero

Prokaryote

a single-celled organism that does not have a nucleus or membrane-bound organelles; examples are archaea and bacteria

Ribosomes

A complex of rRNA and protein molecules that functions as a site of protein synthesis in the cytoplasm

Rough ER

The portion of the ER with ribosomes attatched

Selective Permeability

A property of biological membranes that allows them to regulate the passage of substances across them

Smooth ER

The portion of the ER that is free of riobosomes

Sodium Potassium Pump

transport protein in the plasma membrane of animal cells that actively transports sodium out of the cell and potassium into the cell.

Solute Potential

A component of water potential that is proportional to the molarity of a solution and that measusres the effect of solutes on the direction of water movement; can be positive or negative

Stomata

microscopic pore surrounded by guard cells in the epidermis of leaves and stems that allows gas exchange between the environment and the interior of the plant

Stroma

fluid of the chloroplast surrounding the thylakoid membrane; involved in the synthesis of organic molecules from carbon dioxide and water.

Thylakoid

a flattened membrane sac inside the chloroplast (inner membrane), used to convert light energy to chemical energy.

Transport protein

transmembrane protein that helps a certain substance or class of closely related substances to cross the cell membrane.

Cell Membrane

thin flexible barrier that regulates what enters and exits the cell; composed of two layers of lipids (bilayer)

Lysosomes

membrane-bound sac containing hydrolytic enzymes that can break down proteins, nucleic acids, and polysaccharides (suicide sacs)