Exam II Flashcards
Ch. 4 & 5
The cell theory includes the following generalizations about cells:
a. all organisms consist of one or more cells
b. the cell is the smallest unit of life
c. each new cell arises from another cell
d. a cell passes hereditary info to its offspring
The surface to volume ratio of a cell:
limits cell size and influences cell shape
Cell membranes are characterized mainly by the presence of:
Phopholipid bi-layer
Unlike eukaryotic cells, bacterial cells:
have no nucleus
Multiple species of single-celled organisms sometimes live together in a mass of slimy polysaccharides that they secrete which is called:
biofilm
The function of the nucleus within eukaryotic cells is:
To separate the cell’s DNA from the rest of the cytoplasm and to control the passage of certain molecules bw the nucleus and the cytoplasm
I has a double lipid bilayer that surrounds the nucleus, has pores, and is continuous with the membrane of the ER (Endoplasmic Reticulum)
the nuclear envelope
The following organelles are components of the endomembrane system:
rough and smooth ER, golgi bodies and lysosomes
What differentiates the smooth ER from the rough ER?
the presence of ribosomes which stud the surface of the rough ER
This structures are the primary cellular sites for the production of proteins:
ribosomes
This organelle, which looks like a stack of pancakes, modifies proteins and lipids then sorts, packages, and ships the finished products to lysosomes or to the plasma membrane:
Golgi body
These are common in plants but not animals:
chloroplasts and central vacuoles
This contain powerful enzymes and are the main organelles where intracellular digestion/the breakdown of waste products occurs:
lysosomes
This organelle is where aerobic respiration occurs, which includes the synthesis of ATP. They are often called the powerhouse of the cell:
mitochondria
organelles and plant cells that function in photosynthesis or storage are:
plastids
structural features that contain the protein actin and help to strengthen and change the shapes of eukaryotic cells are:
micro-filaments
Which junction allows communication bw animal cells?
gap junction
In this reaction, reactants have more free energy than the products, ends with a net release of free energy;
exergonic reaction
Enzymes increase the rate of a given reaction by lowering what kind of energy?
activation energy
Characteristics of enzymes:
control the speed of a reaction, change shape to facilitate certain reactions, may place physical stress on the bonds of the substrate, and may require cofactors
Enzymatic reactions can be affected by:
pH, Salinity, temperature, and cofactors
In metabolic pathways that are regulated by feedback inhibition, the “product” inhibits the activity of the:
First enzyme
Allosteric inhibition of enzymes is generally a result of:
binding regulatory molecules at the allosteric site
metabolic pathways in which one molecule accepts electrons from another molecule
redox reaction
Organized series of reaction steps in which membranes-bound arrays of enzymes and other molecules give up and accept electrons in turn.
electron transfer chain
The rate of diffusion through a semi-permeable membrane are characteristics of;
a. steeper concentration gradients
b. higher temperatures
c. size of molecule diffusing
A cell placed in a hypotonic solution will swell. True or False
True
In simple diffusion across a membrane solute moves in which direction?
from an area of high concentration to an area of low concentration
The method of movement that requires the expenditure of ATP molecules is:
active transport
A red blood cell will swell and burst when placed in what kind of solution?
Hypotonic
This molecule needs a transport protein to cross the cell membrane:
glucose
What do white blood cells use to capture and destroy foreign particles in the blood?
phagocytosis
What is osmosis?
the diffusion of water across a membrane
Name two structures single cell organisms use to move through their environments:
flagellum and pseudopod
