Enzymes ____
a. enhance reaction rates
b. are affected by pH
c. act on specific substrates
d. All of the above
The main energy carrier molecule in cells are
ATP molecules
If a biologist said that the human body might be getting its power from bacteris like cell organellas, he would be refering to,
the mitochaondria in our cells that may have originated as endosymbiotic bacteria
Which one of the following is a correct biochemical sequence in the Krebs cycle?
B. Isocitrate--ketoglutarate
Which of the following junctions permit cytoplasmic interconnections between cells?
a. gap junctions
b. plasmodesmata
c. adhering junctions
a. gap junctions
b. plasmodesmata
A single-celled freshwater organism, such as a protistan, is transferred to saltwater. Which of the folowing is likely to happen?
C. The cell shrinks and plasmolysed
The method of movement that requires the expenditure of ATP molecules is
Active transport
The action of white blood cell engulfing a bacterium is
phagocytosis
endocytosis
Enzymes
are very specific
act as catalysts
are organic molecules
have specifc shapes that control their activites
4 of the 5 answers listed below affect the rate of an ensymetic reaction. Select the except...
C. presence of hormones
Plants need which of the following to carry out photosynthesis?
B. CO2
Glycolysis
a. occurs in the mitochondria
b. happens to glucose only
c. results in the production of pyrvate
d. occurs in the cytoplasm
e. c and d of the above
c. results in the production of pyrvate
d. occurs in the cytoplasm
e. c and d of the above
In the breakdown of glucose, a phosophorylated sixcarbon compound is split into two three-carbon componds. The three carbon compound is called
c. acetyl-CoA
The Kreb cycle takes place in the
d. mitochondria
The oxygen released in photosynthesis comes from
d. water
Thylakoid disks are stacked in groups called
a. Grana
The light dependent reactions of photosynthesis
a. involve photolysis of water
The first stable compound produced from CO2 in the light dependent ractoin or Calvin cycle is
a. Phosphoglycerate (PGA)
Allosteric inhibitors interfere with the function of an enzyme by
a. altering the shape of the enzyme
Diffusion
The random movement of molecules or ions from an area of high concerntration to an area of low concentration
Osmosis
The movement of water across any selectively permeable membrane in response to a concentration gradient
Isotonic Solution
Equal concentration of ions in solution and cell
Water: neither lose nor gain
Hypertonic Solution
Higher concentration of ions in solution that in cell
Ocean water: Draws watear out, cells lose water
Hypotonic Solution
Lower concentration of ions in solution that in cells
Distilled Water: Draws water in, cells burst because too much water
Plasmolysis
Membrane loses water
Turgor pressure
The pressue of a plant cell's contents against its cell wall
Passive Transport
Without the expenditure of energy.
Passive transport resluts in equal concentrations of a molecule on the 2 sides of membrane
Active Transport
Moves molecules against a concentration gradient and requires energy.
Cells use the energy of ATP to move ions across the membrane
Facilitated Diffusion
Depends on the action of molecules in the membrane that help or facilitate transport
Permease
Phagocytosis
Cells engulf relatively large particles
Endocytosis
Cell takes in tiny amounts of material in vesicles that arise by the inward folding of the plasma membrane
Pinocytosis
Cell takes up any bits of liquid and dissolved molecules
Exosytosis
Cell accumlates molecules to export in membrane-enclosed vesicles
Plasmodesmata
Only in cells
Allows material to pass directly from cell to cell
Gap Junction
Animal cells
Allows material to pass directly from cell to cell
Adhering Junctions
Allow the passage of molecules while strengthening the connections between adjacent cells
Lose connection
Tight Junctions
Fuse membranes of adjacent cells
Keep fluids from passing between them
Cell to cell communication
Plasmodesmata are tiny channels between plant cells through which flow thin streams of cytoplasm and sometimes thin strands of smooth ER
Fireflies have enzyme luceferase and ATP turns it into luceferia
Then photon turns to light
Exothermic (exergonic)
All processes that release energy
Endothermic (endergonic)
All processes that require an input of energy
Enzymes
Speed up chemical reactions
ALL ARE PROTEINS
Things that affect enzymes
Temperature
pH
Salt Concentration
Anabolism
Two coming together to make one
Energy taken in
Catabolism
One breaking into two
Energy is released
In our saliva there is the __________ enzyme
sal. amylase
Inhibitors
Molecule that changes the activity of enzymes-either increasing or decreasing
Steric Inhibitor
A molecule that binds to an enzyme's active site, preventing substrate from binding
Competes with substrate for active site
Replaces substrate at the active site
Allosteric Inhibitor
Does not compete with the substrate but binds to another site on the enzyme in such a way that the active site on the enzyme in such a way that the active site no longer functions
Changes the shape of the enzyme's active site
Autotrophs
Organisms that make their own food or obtain energy and synthesize organic molecules from inorganic material
Provide energy
Hetertrophs
Obtain chemical energy from other organisms
Can't make own energy
Metabolism
Complex network of biochemical conversions that are collectively
Cellular respiration
oxygen-dependant process by which cells extract energy from food molecules
