Show:
Molecules
Macromolecules
Organelles and Cells
Organ Systems
100
What do competitive inhibitors block, and why is this a problem?
They block the active site of an enzyme, which prevents the substrate from reacting with it.
100
Which of the three parts of a nucleotide allows for genetic diversity?
The nitrogenous base
100
What feature of the phospholipid bilayer allows it to be semi-permeable?
They have polar, hydrophilic heads and nonpolar, hydrophobic tails.
100
Why is the small intestine covered in villi?
They increase the available surface area for absorption.
200
What about the structure of carbon allows it to form covalent bonds?
It is tetravalent, or has four valence electrons.
200
There are three parts of an amino acid. Which part determines the shape and function?
The "r" group
200
Why do lysosomes contain toxic and digestive enzymes?
It allows them to digest macromolecules or perform apoptosis if needed.
200
Why does the nephron contain so many turns, such as the Loop of Henle?
It can have a greater surface area for reabsorption and secretion in a limited amount of space.
300
Why are fish able to live underwater in freezing cold conditions?
Water is less dense as a solid, so ice floats on the surface, insulating the water beneath.
300
Why don't oil and water mix?
Oil is a lipid, meaning it is nonpolar and therefore does not dissolve in water.
300
What feature of thylakoid membranes allow for increased light absorption?
Stacks of membranes for increased surface area
300
How do arteries withstand the pressure needed to pump blood to the body?
They have very thick, muscular walls.
400
Water's properties of adhesion and cohesion allow for what crucial process in the water cycle?
Transpiration
400
What two processes are enabled by the fact that nucleotides are joined by hydrogen bonds, which break easily?
Replication and Transcription
400
What allows a neuron to transmit messages from the central nervous system to the extremities?
Its long axon and dentrites
400
How are muscles and bones connected to each other to allow for movement?
With tendons (muscle to bone) and ligaments (bone to bone)
500
Why is water known as the universal solvent?
It is a polar molecule, so it can dissolve all other polar or ionic molecules.
500
Humans can digest starch, but not cellulose. What feature of starch molecules allows enzymes to break them down?
Their helical shape, or ring shape.
500
What two structures in muscle cells allow them to contract and relax?
Actin and myosin filaments
500
Why are the alveoli covered in capillaries?
The gas exchange between oxygen and carbon dioxide occurs in them.