Bio Principles Exam #2 Review

The simplest structural unit of a living organism

Cell

Single celled

unicellular

Comprised of multiple cells

Multicellular

Most enzymes are proteins, but some are not. True or false.

True

Most proteins are enzymes, but some are not. True or false

False

Who observed box shaped structures in cork and named them cells?

Robert Hooke

What are the three components of cell theory?

Cells are the fundamental units of life
All living organisms are composed of cells
All cells come from pre-existing cells

What is an idea/rule that explains have something happens?

Unifying principal

The scientific theory that living things could arise from nothing/nonliving matter

Spontaneous generation

Who disproved spontaneous generation?

Francesco Redi

All cells have the same basic chemical composition. True or false.

True

Information is passed down from cell to cell

Hereditary

What are cells?

Sacks of stuff

Almost everything that composes the inside of a cell except nucleus

Cytoplasm

Is a gelatinous liquid that fills the inside of a cell, it is composed of, 60 to 90% water, salts, and various organic molecules

Cytoplasm

The aqueous (water) component of the cytoplasm, within which various organelles and particles are suspended

Cytosol

Separates the internal environment from the external environment

Cell membrane

What does the cell membrane allow the cells to do?

Regulate internal composition

What two things about membranes are similar across organisms?

Structure and function

What is the cell membrane primarily composed of?

phospholipid bilayer

Having an outward/water, facing, polar, hydrophilic "head" and an inward facing, non-polar, hydrophobic "tail"

Amphipathic

What macromolecules are in/on the membrane?

Proteins, cholesterol, carbohydrates

What are a membranes characteristics determined by?

The chemical properties of its constitutes(component parts)/cholesterol

Where can proteins be found?

Embedded internally, or externally to the surface of the phospholipid bilayer

What assist with the movement of molecules across the bilayer?

Proteins

Peripheral membrane proteins are ________ bonded to either membrane surface.

Non-covalently

Anchored membrane proteins are _______ bonded to lipids that are inserted into the membrane

Covalently

Sugar can dissolve in water. True or false

True

Carbohydrates are polar and hydrophilic molecules. True or false

True

Carbohydrate is attached to a protein

Glycoprotein

Carbohydrate is attached to a lipid

Glycolipid

Membrane proteins may consist of one or multiple _______ subunits.

Polypeptide

What macromolecules are involved in cell-to-cell recognition?

Carbohydrates

Cells of the immune system use _______ to differentiate between self and non-self components

Carbohydrates

Where is cholesterol found?

Mostly between phospholipids (interacting with their hydrophobic tails) on the inside of the bilayer

Cholesterol alters membrane _______ due to its hydrophobic ringed structure that interacts with the phospholipid tails within the bilayer

Fluidity

What in the membrane will alter its fluidity?

Amount of cholesterol present

How easy it is for molecule to pass through

Permeable

The cell membrane is a solid, unchangeable structure. True or false

False

Most of the lipids and proteins move vertically (up and down) true or false

False

What term is used to describe the membrane?

Fluid mosaic

What is the gentle adhesive that helps the phospholipids and bilayer stick together?

Weak Van Der Waals interactions

The hydrophobic interior of the bilayer prevents _______ of polar molecules and ions through the membrane

Diffusion

How do phospholipid membranes differ in lipid composition?

Fatty acid chain length, degree of saturation, and polar groups

Membrane fluidity is influenced by _______ and _______.

Lipid composition and temperature

As temperature decreases, fluidity decreases. True or false

True

Those that are least partly embedded in the phospholipid bilayer(hydrophobic regions interact with hydrophobic interior membranes)

Integral membrane proteins

Proteins that covalently attach to fatty acids or other lipid groups within the cell membrane

Anchored membrane proteins

Are not embedded in the bilayer-polar or charged regions of these proteins interact with exposed parts of integral membrane proteins or with charged heads of phospholipids-do not contain exposed, hydrophobic R groups

Peripheral membrane proteins

A type of integral membrane proteins that extends all the way through the bilayer

Transmembrane

Composed of many carbohydrates attached to a protein

Proteoglycan

Can impact membrane fluidity, but mostly play roles in cell-to-cell communication and adhesion

Carbohydrates

Allows some, but not all, substances to pass through them

Selectively permeable

Substances pass through cell membranes via two types of...

Transport mechanisms

What are the two types of transport mechanisms?

Passive transport and active transport

Type of transport mechanism, in which substances diffuse down a concentration gradient, and do not require energy

Passive transport

Type of transport mechanism, in which substances across the membrane with the assistance of specialized membrane proteins that require energy

Active transport

What are the two types of passive transport?

Simple diffusion and facilitated diffusion

No help is needed to diffuse

Simple diffusion

Help is needed from proteins to defuse

Facilitated diffusion

The random movement of particles toward a state of equilibrium(even distribution within a solution)

Diffusion

A net movement from regions of higher concentration to regions of lower concentration

Down a concentration gradient

Systems tend to disorder

Entropy

What allow molecules to move through the phospholipid by layer of the cell membrane?

If they are small enough and/or share chemical characteristics with the phospholipids that make up the membrane

Water-based

Aqueous

Diffusion in water is _______

Slow

The speed at which diffusion occurs depends on _______, _______, ______, _______ and _______.

Diameter, temperature, concentration gradient, area and distance

_______ molecules diffuse faster

Smaller

Particles move _______ when temperatures increase

Faster

The _______ the concentration gradient is, the more rapidly substances diffuse

Greater

A _______ surface area allows for faster diffusion

Larger

How far the substance must diffuse

Distance

Electrically charged (ions) or larger polar molecules (like amino acids and sugars) do not pass through the membrane because they are strongly _______.

Hydrophilic

Form channels across the membrane

Channel proteins

Channels for movement of water across membranes

Aquaporins

Channels for passage of ions across membranes

Gated ion channels

Bind to a solute (non-covalently, reversibly) and transport them through the membrane (to speed up diffusion)

Carrier proteins

Facilitates passage of glucose across the membrane

Glucose transporter

A type of channel proteins that allow specific ions to pass through

Ion channels

Channels which open when stimulated by a ligand (a chemical signal)

Ligand-gated channel

Channels which open when stimulated by a change in electrical charged difference across the membrane

Voltage-gated channels

Carrier proteins transport polar molecules such as _______ and _______

Sugar and amino acids

What happens to carrier proteins when a solute binds to them?

Change shape