BIO 160 Chapter 5 Flashcards
What is energy?
The capacity to cause change
kinetic energy
energy in motion
potential energy
stored energy
Conservation of Energy
- energy cannot be created or destroyed
2. energy can be converted from one form to another
entropy
measure of disorder or randomness in a system
heat
is a type of kinetic energy and product of all energy conversions
chemical energy
- arises from the arrangement of atoms and
* can be released by a chemical reaction.
cellular respiration
• the energy-releasing chemical breakdown of fuel
molecules (ie glucose)
• the storage of that energy in a form the cell can use to
perform work (ie ATP)
energy used by humans
- ~34% to do work
* ~66% as heat
calorie
– A calorie is the amount of energy that can raise
the temperature of one gram of water by 1 ⁰C.
• Food Calories are kilocalories, equal to 1,000 calories.
• The energy of calories in food is burned off by many
activities.
ATP
• acts like an energy shuttle
• stores energy obtained from food
• releases it later as needed
• consists of an organic molecule called adenosine plus a
tail of three phosphate groups and
• is broken down to ADP and a phosphate group, releasing
energy.
phosphate transfer
– ATP energizes other molecules by transferring phosphate groups. – This energy helps cells perform • mechanical work, • transport work, and • chemical work.
ATP cycle
– Cellular work spends ATP continuously.
– ATP is recycled from ADP and a phosphate group
through cellular respiration.
– A working muscle cell spends and recycles up to
10 million ATP molecules per second.
metabolism
total of all chemical reactions in an organism
activation energy
– Activation energy activates the reactants and
• triggers a chemical reaction.
– Enzymes reduce the amount of activation energy
required to break bonds of reactant molecules.
– Enzymes can function over and over again.
– Many enzymes are named for their substrates, but
with an –ase ending
induced fit
– An enzyme is very selective in the reaction it
catalyzes.
– Each enzyme recognizes a substrate, a specific
reactant molecule.
• The active site fits to the substrate, and the enzyme
changes shape slightly.
• This interaction is called induced because the entry of
the substrate induces the enzyme to change shape
slightly
feedback regulation
– Some products of a reaction may inhibit the
enzyme required for its production.
• This is called feedback regulation.
• It prevents the cell from wasting resources.
enzyme inhibitors
• Penicillin blocks the active site of an enzyme that bacteria
use in making cell walls.
• Ibuprofen inhibits an enzyme involved in pain signaling.
• Many cancer drugs inhibit enzymes that promote cell
division.
transport proteins
- are located in membranes and
* help move substances across a cell membrane
passive transports
- Diffusion
- Osmosis
- Facilitated diffusion
active transports
• ATPases (ie pumps)
concentration gradient
a region in which the substance’s density
changes.
diffusion
is the movement of molecules so that they spread
out evenly into the available space
osmosis
diffusion of water across a selectively permeable
membrane
facilitated diffusion
movement of molecules so using
a transport protein but does not require energy
hypertonic solution
higher concentration of
solute
hypotonic solution
lower concentration of solute
isotonic solution
equal concentration of solute
osmoregulation
is the control of water balance within a cell or
organism.
plasmolysis
occurs when the cell membrane pulls away from
the cell wall, causing plant to shrivel
turgid
normal
active transport
requires that a cell expend
energy to move molecules across a membrane.
• Na+/K+ pump pumps 2 K+ into the cell and 3 Na+ out
of the cell
exocytosis
the secretion of large molecules
within transport vesicles.
endocytosis
imports material into the cell using
transport vesicles
phagocytosis
(ie “cellular eating”) brings material
into the cell by engulfing food or other
substances within a vacoule or vesicle
role of membranes in cell signaling
– The plasma membrane helps convey signals
• between cells and
• between cells and their environment.
– Receptors on a cell surface trigger signal
transduction pathways that
• relay the signal and
• convert it to chemical forms that can function within the
cell.
phospholipids
• are key ingredients of membranes,
• were probably among the first organic compounds that
formed from chemical reactions on early Earth, and
• self-assemble into simple membranes
explain relationship between heat and entrophy
all energy conversions generate heat, everytime energy is converted, entrophy increases
compare the processes by which a car and a human use “fuel” to perfom work
car -octane+oxygen => combustion =heat energy, kinetic energy of movement => carbon dioxide, water.. HUMAN - Glucose +oxygen=>cellular respiration.. heat energy, ATPs=> carbon dioxide
compare the amout of energy in a calorie, kilocalorie, Calorie
kilocalorie = Calorie, 1000 calories = 1 kilocalorie
explain how ATP powers cellular work
transfer of phospate from triphosphate tail provides energy for cellular work, motor transport, or chemical reaction
explain how ATP is recycled
it is recycled in cellular respiration, ADP=>ATP
explain why enzymes are needed in living organisms
countless chemical reactions constantly change organisms molecular makeup
explain how enzymes are able to speed up chemical reactions
w/ enzymes activation energy is lessened
explain how inhibitor and poison can affect enzyme activity
stop enzymes from creating products
diffusion vs osmosis
diffusion - the movement of molecules spreading out evenly into the available space, osmosis - diffusion of water through a selectivley permeable membrane
passive vs active transport
passive transport - cells don’t expend energy for it to happen, active transport -expends energy to move molecules across a membrane
hypertonic vs hypotonic
hypertonic - higher concentration of solute, hypotonic - lower concentration of solute
endocytosis vs exocytosis
exocytosis - spilling the contents outside the cell, endocytosis- cell takes material in
phagocytosis vs pinocytosis
phagocytosis - cellular eating, pinocytosis - cellular drinking
explain how signal transduction pathways permit environmental stimuli to impact the activities inside cell
enzymes catalyze chemical reactions, receptors tell cell “adrenaline is here” certain things happen in the cell with the intorduction of adrenaline, CELL NEEDS MORE ENERGY
explain why phospholipids were probably some of the first organic compounds to form as life emerged on Earth
all cells have a plasma membrane, when a mixture of phospholipids and water is shaken, phospholipids organize into bilayers
