bio 101 : module 5 study guide

what is the function of the plasma memrane?

physical isolation, regulation of exchange with the environment. communication with the environment, structural support

where is extracellular fluid (ECF) found?

outside of the cell

where is cytosol found?

the full of fluid inside of cell

which organic molecule is the plasma membrane mainly composed of?

cholesterol, receptor proteins, transport proteins, recognition proteins

what is the function of cholesterol in the plasma membrane?

makes membrane stiffer

what is the meaning of the term “bilayer”?

membrane with two molecular layers (phospholipid)

which part of a phospholipid is hydrophilic?

the head

which part of a phospholipid is hydrophobic?

the tail

why is “fluid mosaic” is used to describe plasma membranes?

they are composed of a dynamic, fluid phospholipid bilayer with embedded proteins and other molecules

what are the functions of proteins in the membrane?

transport, structural, recognition, cell signaling

what is the function for transport in the membrane?

regulate movement of molecules across the membrane

what is the function for structural in the membrane?

anchor cell to the extracellular matrix, anchors proteins near the cell membrane, link one cell to another

what is the function of recognition in the membrane?

sugars attached to proteins allow cells to “recognize” each other (glycoproteins)

what is the function of cell signaling in the membrane?

receptors and enzyme; activation initiates cellular processes

what is impermeable barrier?

nothing passes through the membrane

what is freely permeable barrier?

anything can pass through the membrane

what is selectively permeable barrier?

allow some things to pass through, while blocking others

what can easily pass through the cell membranes?

size (small molecules) , attraction of water, polarity, charge

what can not easily pass through the cell membranes?

large molecules, hydrophilic, ions

what is diffusion?

the net movement of particles from a region of higher to lower concentration

what is osmosis?

water diffuses across the membrane in a process

what is passive transport (simple diffusion)?

transport through the membrane that is unaided by proteins, no energy required, and can move across a concentration gradient high to low

what is facilitated diffusion?

provides a “pathway” for large or hydrophilic molecules to move along their concentration; no energy is required; high to low concentration; requires a transport protein

what is active transport?

used to move molecules against their concentration gradient; uses protein channels and requires energy (ATP) to “pump” substances into or out of the cell

how does the concentrations of the substance at equilibrium on each side of the membrane?

there is an equal concentrations on both sides of the membrane

do you need energy for diffusion?

no

do you need protein channels for diffusion?

no

what are the gases that can easily move into or out of cells?

oxygen (O2) and carbon dioxide (CO2)

in osmosis you are talking about the movement of one thing only:

water

what is the concentration of water movement in osmosis?

high concentration to low concntration

is the water solute or solvent in the solution of osmosis?

solvent

what is hypertonic?

net water flow out of the cell (high concentration)

what is hypotonic?

net gain of water into the cell (low concentration)

isotonic

no net gain or loss of water

do you need the energy to do facilitated diffusion?

no

do you need a protein channel to facilitate diffusion?

yes

what is the concentration for facilitated diffusion?

high concentration to low concentration

do you need energy to do active transport?

yes

do you need a protein channel to do active transport?

yes

what is the concentration of the substance to be pumped/pushed for active transport?

low concentration to high concentration

which energy molecule is required for active transport?

ATP

what is endocytosis?

the movement into the cell

what is exocytosis?

the ejection of materials from the cell

what is pinocytosis?

type of endocytosis where the cell engulfs liquids or dissolved substances (“cell drinking”); the cell membrane forms small vesicles around the liquid, bringing it into the cell

what is phagocytosis?

type of endocytosis where a cell engulfs solid particles (“cell eating”); the cell's membrane extends around the solid particle, forming a pocket that eventually pinches off to form and break down the engulfed material

what is vesicular transport?

when a large material moves into or out of cells in membranous vesicles

what is energy

the capacity to cause change

what is bioenergetics?

the processing of energy by living organisms

what are the two types of energy?

potential and kinetic

what is potential energy?

stores energy; matter

what is kinetic energy?

released (active) energy; in motion

what type of energy is a block of wood?

potential energy

what type of energy is a photon?

kinetic energy

what type of energy is heat?

kinetic energy

what type of energy is food?

potential energy

what mechanical energy is used for in animals?

movement

what is the first law?

law of conservation of energy → energy can neither be created nor destroyed; however, it can be transferred or transformed from one form to another; the total amount of energy is constant

what is the second law?

law of entropy → when energy is transformed from one type into another there is always lost useable energy; loss is usually in the form of heat

what is entropy?

a measure of disorder in a system

what is the energy through our biosphere?

solar powered, producers, consumers, decomposers, heat lost

what is solar powered?

energy enters the system as light (sunlight)

what is producers?

convert light energy into chemical energy; photosynthetic organisms (plants, algae)

what is consumers?

chemical energy is passed; organisms that feed on plants (animals)

what is decomposers?

breaks down the consumers; break down waste products and the remains of dead organisms (fungi, bacteria)

what is the energy source for earth?

sun

what is metabolism?

all of the biochemical reactions that happen in a cell

what is the catabolism?

one part of metabolism is breakdown reactions (degradation)

what is anabolism?

one part of metabolism is build up (synthetic) reactions

where does hydrolysis happen?

catabolism

where does dehydration synthesis happen?

anabolism

what reactions consume energy?

anabolism

what reactions release energy?

catabolism

what are REDOX reactions?

one molecule loses electrons (oxidation) while another gains electrons (reduction)

what does OIL stand for?

oxidation is losing (electrons) → molecules become more positive

what does RIG stand for?

reduction is gaining (electrons) → molecules become more negative

NAD → NADH

reduction

Fe2+ → Fe3+

oxidation

NADPH → NADP+

oxidation

C6H12O6 → CO2

oxidation

CO2 → C6H12O6

reduction

how do enzymes work as biological catalysts?

protein that speed up reactions

how do enzymes speed up reactions?

activation energy is needed to start a chemical reaction; happens when they are lower energy

what is denature?

when temperature, pH, or salt level are changed in the enzyme

what is active site?

where the substrate binds and the reaction happens

what is substrate?

the molecule that an enzyme acts on bring about a chemical reaction

what is induced fit?

when the enzyme slightly changes shape to better fit the substrate after binding

what is an inhibitor?

slows down or stops an enzyme’s activity

what is competitive inhibition?

binds to an active site, blocking the substrate from binding by occupying the active site

what is non-competitive

binds to allosteric site; changes enzyme shape from preventing substrate binding even if it fits

what is the structure of ATP?

nitrogenous base adenine, sugar ribose, three phosphate groups

what are the functions of ATP in cells?

power many reactions in the cell, active transport, muscle contraction, cell division

ATP releasing cycle

ATP → ADP + Pi + energy

ATP rebuild cycle

ADP + Pi + energy → ATP

what process creates ATP from glucose?

cellular respiration