Biology 101 Chapter 6 Review
Which of the following statements most accurately describes the first law of thermodynamics?
Energy cannot be created or destroyed but it can be changed from one form to another.
Which of the following consistent with the laws of physics governing energy?
Eventually, sunlight that is absorbed on the earth returns to the atmosphere as dispersed heat
Which hypothesis, based on the two laws of thermodynamics as applied to cells, would determine if something is a living cell or no?
If something uses energy to make itself more organized, then it is alive.
Determine the accuracy of the following statement: A reactant will always produce the same type of product, regardless of the type of enzyme(s) present.
The statement is inaccurate because a particular reactant can be substrate for various enzymes, each resulting in a different product.
If there are 12 different intermediate products produced during production of a molecule in a cell, we can expect that there
are about 12 enzymes, at lest one responsible for each step in the metabolic pathway.
If an enzymatic reaction was controlled by feedback inhibition, we would expect it to stop
as soon as a critical level of end product builds up.
The metabolic pathways of photosynthesis and cellular respiration
both involve oxidation and reduction reactions
Which of the following is an example of chemical work within a cell?
building a protein
Most cells use a tremendous amount of ATP
but the amount of stored ATP is not great because our body constantly generates ATP from ADP+ P
The main reason that ATP is considered the energy currency in cells is because it
contains accessible energy in phosphate bonds
Chemical reactions that require an input of energy are
endergonic reactions
What is the equation for photosynthesis?
energy + 6CO2 + 2H2O --> C6H1206 + 602
When a cell uses substantial energy to organize its cell contents to a greater degree that the organization that exists outside the living cell
entropy is decreased
Enzymes have "specificity". This means that they
have a particular substrate
Each enzyme has a particular substrate because enzymes
have active sites complementary in shape to their substrates.
The function of an enzyme is to
increase the rate of a metabolic reaction.
Heat
is an unusable form of energy
Which of the following molecules is an enzyme?
lipase
Which of the following by-product of photosynthesis?
oxygen
A reaction that is "endergonic, anabolic, nonspontaneous, and has a positive delta G" could be describing
photosynthesis
Most enzyme are
protein molecules
The addition of electrons and/or hydrogen from a substrate is called what?
reduction
Enzymes
require coenzymes and/or cofactors for optimal functioning
Whether or not an enzyme is present and active within a cell depends on all of the following except
the presence of specific steroids in the cytoplasm
The ultimate source of energy for the majority of organisms on Earth is
the sun.
In feedback inhibition of a metabolic pathway, where does the inhibitor bind?
to the enzyme of the first reaction
Which of the following will increase enzyme activity?
Change to optimum pH for the reaction
Which of the following is a true statement regarding energy and chemicals
Chemicals, but not energy, may cycle through living things
ATP can be broken down into
ADP plus phosphate plus energy
Chloroplasts and mitochondria are both involved in redox reactions because
Carbon dioxide is reduced during photosynthesis and carbohydrates are oxidized during cellular respiration
Which statement most accurately describes the second law of thermodynamics?
Energy cannot be changed from one form to another without a loss of usable energy
Which of the following is an accurate statement about metabolic pathways?
Metabolic pathways often intersect one another.
Where within the cell is the majority of ATP produced?
Mitochondria
Which of the following is a correct statement about the second law of thermodynamics and entropy?
The amount of disorder in the universe is always increasing
Assess the following statement for accuracy; All of the energy that a plant stores in the bonds of glucose is available to an animal to power its muscles
The statement is inaccurate because the second law of thermodynamics states that energy cannot be converted from one form to another without a loss useable energy.
Which of the following statements is true about enzymes?
They catalyze only one specific type of reaction
Assess the following statement for accuracy: Because the inside of a cell is more organized that the outside, the inside of the cell has increased entropy
This statement is inaccurate because as order increases, entropy decreases.
Which of the following is a true statement regarding oxidation reactions?
Whether or not oxygen is involved, a reaction is considered and oxidation reaction if elections are lost.
We often say that we need food for energy. Ina biological sense, is that correct?
Yes, because the food we eat has potential energy in its structure and this chemical energy can be converted into mechanical.
What is a metabolic reaction called that involves one reaction releasing energy to provide energy for a second reaction that requires energy?
a coupled reaction
What is a metabolic reaction called that involves one reaction releasing energy to provide for a second reaction that requires energy?
a coupled reaction
The location in which the enzyme and the substrate complex is called the
active site
Which of the following is not cellular function of ATP?
adding structural integrity to the cell membrane
The term metabolism refers to
all the chemical reactions that occur in a cell
ATP contains
an adenine base, a ribose sugar, and three phosphate groups
In a coupled reaction
some of the energy released in one reaction is used to drive another reaction forward
The reason an increase in substrate concentration does not increase the reaction rate indefinitely is because
the active site will become saturated with substrate and the enzyme will not be able to go any faster.
While science cannot describe "thinking" in physical terms, we are certain that the process involves metabolism inside brain cells. With positron emission tomography (PET scan), it is possible to inject short-lived isotopes and image the regions of the brain that have the most active metabolism during various mental activities. However
the cellular energy expended in thinking must be less that the chemical bond energy supplied in food to these brain cells.
The specificity of an enzyme to a substrate is currently best explained by
the induced-fit model
