Ch 3 Bioenergetics Flashcards
What is anabolism?
the synthesis of molecules
What is catabolism?
the breakdown of molecules
Name the four elements that compose over 95% of the human body. Place them in order from greatest to least
oxygen (65%), carbon (18%), hydrogen (10%), and nitrogen (3%)
What is the function of a cell membrane?
it regulates the passage of various types of substances in and out of the cell and to enclose the components of the cell
_____ is broadly defined as the total of all cellular reactions and includes chemical pathways that result in the synthesis of molecules (anabolic reactions), as well as the breakdown of molecules (catabolic reactions).
metabolism
Cells possess chemical pathways that are capable of converting foodstuffs into a biologically usable form of energy. This metabolic process is termed _____.
bioenergetics
Identify a characteristic of the cells of the skeletal muscle fibers.
a) They have a nuclear membrane that has two lipid bilayers.
b) They have an impermeable cell membrane.
c) They have a single nucleus.
d) They have multiple nuclei.
d) they have multiple nuclei
The organelle within the cytoplasm that is involved in the oxidative conversion of foodstuffs into usable cellular energy is the _____.
a) mitochon
The organelle within the cytoplasm that is involved in the oxidative conversion of foodstuffs into usable cellular energy is the _____.
mitochondri(on/a)
True or false: Chemical bonds that contain relatively large amounts of kinetic energy are known as high-energy bonds.
False; chemical bonds that contain relatively large amounts of POTENTIAL ENERGY are known as high-energy bonds
In skeletal muscle fibers, the cell membrane is also known as the _____.
sarcolemma
what is an exergonic reaction?
a reaction that gives off energy as a result of chemical processes
what is an endergonic reaction?
a reaction that requires energy to be added to the reactants before the chemical process can take place
What is a coupled reaction?
the free energy from one reaction is used to drive the second reaction
- the first reaction is typically exergonic and the second reaction is typically endergonic (since it gets energy from the exergonic to start a chemical reaction)
The _____ is a large, round body within the cell that contains the cellular genetic components (genes).
nucleus
The cytoplasm is also known as _____ in muscle cells.
sarcoplasm
What is the purpose of an enzyme in a cellular chemical reaction?
it regulates the speed at which the reaction takes place; it can speed up (catalyze) or slow down a reaction
The energy required to initiate chemical reactions is called the _____ _____
activation energy
a hydrogen atom contains how many protons and electroms?
1 proton, 1 electron; that’s why H+ is transferred constantly for oxidation-reduction reactions.
The pockets in an enzyme that are formed from the ridges and grooves located on the enzyme are called _____.
a) allosteric sites
b) energy sites
c) inactive sites
d) active sites
d) active sites
Nicotinamide adenine dinucleotide (NAD) is capable of transferring electrons to which vitamin?
vitamin b3
Flavin adenine dinucleotide (FADH2) is capable of transferring electrons to which vitamin?
vitamin b2
What type of enzyme adds a phosphate group to the substrate?
Kinases
What type of enzymes remove hydrogen atoms from their substrates?
dehydrogenases
what type of enzyme catalyzes oxidation-reduction reactions involving molecular oxygen?
oxidases
what type of enzyme rearranges atoms within their substrate molecules to form structural isomers?
isomerases
The activity of an enzyme is measured by the _____.
a) number of hydrogen atoms transferred during the reaction
b) rate at which its substrates are converted into products
c) rate at which it forms the enzyme-substrate complex
d) number of carbon atoms in it
b) rate at which its substrates are converted into products
What is the significance of the active site of an enzyme?
a) It helps the nuclear material to process the cellular proteins.
b) It helps in the conversion of DNA to mRNA.
c) It helps the specific enzyme to adhere to a particular reactant molecule.
d) It helps in the reproduction of unicellular organisms.
c) It helps the specific enzyme to adhere to a particular reactant molecule.
What happens when there is an increase in the acidity of body fluids?
a) It results in a decrease in the temperature of the bodily fluids.
b) It results in a decrease in the ability to provide ATP for muscular contraction.
c) It results in an increase in the temperature of the bodily fluids.
d) It results in an increase in the ability to provide ATP for muscular contraction.
b) It results in a decrease in the ability to provide ATP for muscular contraction.
What is the most common dietary disaccharide in the U.S.?
sucrose
What are the factors that alter enzyme activity?
temperature and pH
Accumulation of large quantities of hydrogen ions results in a(n) _____ of bodily fluids.
a) increase in the pressure level
b) decrease in the acidity
c) increase in the temperature
d) decrease in the pH
d) decrease in the pH
What are the two most common forms of polysaccharides?
starch and cellulose
True or false: 1 gram of carbohydrate yields approximately 9 kcal of energy.
FALSE; 1g of carbohydrate yields approx. 4kcal of energy
During exercise, individual muscle cells break down glycogen into glucose. This process is known as _____.
glycogenolysis (-lysis meaning breakdown and glycogen from what it was AT FIRST so if glycogen -> glucose then glycogen-lysis)
This monosaccharide is considered to be the sweetest of the simple carbohydrates
fructose (think of it like fruit = sweet fructose)
Fatty acids consist of long chains of carbon atoms linked to a _____ group at one end.
a) hydroxyl
b) carboxyl
c) amine
d) amide
b) carboxyl
Humans lack the enzymes necessary to digest _____, and thus it is discarded as waste in the fecal material.
a) glycogen
b) fructose
c) cellulose
d) starch
c) cellulose
Proteins are formed by linking amino acids by chemical bonds called _____.
peptide bonds
What is the primary type of fat used by muscle cells for energy?
fatty acids
What is the end product of glycolysis?
pyruvate!! REMEMBER THIS
What does the structure of ATP consist of? (Hint: there are three main parts)
1) an adenine portion
2) a ribose portion
3) three linked phosphates
The Krebs cycle completes the oxidation of acetyl CoA using _____ and _____ as electron (energy) carriers.
a) NAD+; FADH2
b)NADH2; FAD
c) NADH; FADH
d) NAD+; FAD
d) NAD+; FAD
When phosphocreatine (PC) reacts with adenosine diphosphate (ADP) in the presence of creatine kinase, it releases adenosine triphosphate (ATP) and _____.
a) alanine
b) creatine
c) leucine
d) phosphine
b) creatine
What are the steps to oxidative phosphorylation?
1) formation of Acetyl-CoA
2) oxidation of Acetyl-CoA
3) production of ATP
In addition to the production of Nicotinamide adenine dinucleotide (NADH) and flavin adenine dinucleotide (FADH), the Krebs cycle results in the direct formation of an energy-rich compound called _____.
a) uracil triphosphate
b) cytosine triphosphate
c) guanosine triphosphate
d) thiamine triphosphate
c) guanosine triphosphate
What is the aerobic production of ATP that occurs in the mitochondria?
oxidative phosphorylation
In Krebs cycle, acetyl-CoA combines with oxaloacetate to form
a) malate
b) fumarate
c) succinate
d) citrate
d) citrate
True or false: Enzymes that function independent of modulators are known as allosteric enzymes.
FALSE; enzymes that are regulated by modulators are called allosteric enzymes; modulators affect enzyme activity
Identify the terms used to describe the pathway responsible for the process of oxidative phosphorylation. (Check all that apply.)
a) the nuclear chain
b) the glucose chain
c) the cytochrome chain
d) the respiratory chain
c) and d)
the cytochrome chain, the respiratory chain
What is a modulator?
modulators are substances that increase or decrease enzyme activity
What is the rate-limiting enzyme in glycolysis?
phosphofructokinase
Which enzyme is responsible for degrading glycogen to glucose?
a) phosphorylase
b) phosphofructokinase
c) hexokinase
d) enolase
a) phosphorylase
What is the rate-limiting enzyme in the Krebs Cycle?
isocitrate dehydrogenase
