chapter 5 Flashcards
What is/defines the unit of a calorie?
amount of energ needed to raise temperature of 1 gram of water by 1 degree celcius. food Calories are larger, like a kilocalorie, so 1000 calories = 1 Calorie
Long name for ATP
Adenosine triphosphate
What is ATP made of
Adenosine plus a tail of 3 phosphate groups
How does ATP work
Chemical energy is released by breaking down organic molecules (cellular respiration) ATP generates ATP acts like an energy shuttle, stores it, and releases it as needed is then broken down into ADP and a phosphate group, releasing energy (the other phosphate is sent to another molecule)
Metabolism
the total of all chemical reactions in an organism
Enzymes
proteins that speed up chemical reactions by lowering the activation energy for the reaction. enzymes are NOT used up in a reaction, can function over and over
induced fit
Each enzyme recognizes a specific reactant molecule called a substrate the active site fits to the substrate, and the enzyme changes the shape slightly
Enzyme Inhibitors
- Prevent metabolic reactions by binding to the active site
- bind at a remote site
- change enzyme shape
- prevent enzyme from binding to its substrate
Feedback regulation
some products of a reaction may inhibit the enzyme required for its production. prevents cells from wasting resources many antibiotics work by inhibiting enzymes of disease causing bacteria
Transport Proteins
proteins in membrane regulate passage of materials into and out of the cell
Diffusion
Movement from high concentration to low concentration the tendency for molecules of any substance to spread out into the available space
Passive Transport
The diffusion of a substance acros a membrane without input of energy
facilitated diffusion
Some substances do not cross membranes spontaneously. Transported via facilitated diffusion. Specific transport proteins act as selective corridors substrate binds to the protein protein changes shape allows the diffusion of the molecule, creating a passage tunnel for large molecules and shielding from the inner membrane for polar or charged molecules. No energy input is needed
Cells control their Chemical environment using….
Energy Enzymes plasma membrane
Osmosis
diffusion of water across a selectively permeable membrane
hypertonic
higher concentration of a solute, net movement of water is out of cell (crenates)
hypotonic
lower concentration of solute, net movement is out of the cell (burst/lyses, in a plant cell called turgor pressure)
isotonic
equal concentration of solute through out cell, there is NO net movement of water.
Osmoregulation
the control of water balance within a cell or organism. Most animal cells require an isotonic environment to maintain morphology and tonicity
What type of environment do plant cells require?
a hypotonic environment, which keeps cell wallsturgid
What happens as a plant cell loses water?
-cell shrivels
-Its plasma membrane may pull away from the cell wall in the process of
plasmolysis, which usually kills the cell.
Active transport
requires energy to move molecules across a membrane.
-movement is from high to low concentrations
Exocytosis
the secretion of large molecules within vesicles
Endocytosis
takes material into a cell within vesicles that bud
inward from the plasma membrane.
What are the 3 types of endocytosis
- Phagocytosis (cellular eating):a cell engulfs a particle and packages it within a food vacuole
- Pinocytosis (cellular drinking): a cell gulps droplets of fluid by forming tiny vesicles
- Receptor-mediated: a cell takes in very specific molecules
The plasma membrane helps convey signals between…
- Cells
- Cells and the environment
signal transduction pathways
Triggered by receptors on a cell surface, they relay the signal and convert it to chemical forms that can function within the cell
