What is a hypothesis?
A tentative explanation that can be tested by experiments.
What is the process of science?
Observation, question, hypothesis formulation, experiment, support or refute hypothesis
Which of the following is not associated with living things? 1. ability to harvest energy 2. ability to respond to surroundings 3. ability to maintain its internal environment 4. storage of genetic information in proteins 5. ability to reproduce
storage of genetic information in proteins
What are the 4 most abundant chemical elements in a cell?
carbon, oxygen, hydrogen, nitrogen
What are the four major groups of macromolecules?
Proteins, complex carbohydrates, nucleic acids, lipids
A single covalent bond represents the sharing of how many electrons?
2
The versatility of the carbon atom and the reason it is said to be the “backbone of life” is due to the fact that carbon atoms….
have four unpaired electrons in their outer shell
How many hydrogen atoms are present in a hydrocarbon chain of 10 carbon atoms that are held together by 5 single covalent bonds and four double covalent bonds?
14
The unique properties of water are due to the _____ of water molecules and the abiliyt of water to form _____ with other water molecules and with other polar particles.
polarity/hydrogen bonds
Cellulose is made by _____ cells and functions as _______ molecule.
plant/structural
What bond is associated with the formation of complex carbohydrates?
glycosidic linkage
What bond is associated with the formation of Triglycerides?
ester bonds
What bond is associated with the formation of proteins?
peptide bonds
The bonds that hold monomers together in polymers are always?
covalent bonds
Condensation reactions (also called dehydration reactions) are involved in?
the synthesis of a complex carbohydrate and the synthesis of a protein
Of the three subatomic particles that make up atoms, only ____ are directly involved in the formation of chemical bonds?
electrons
Chemical bonds that rely on the attraction of positive and negative charges are ______?
ionic bonds and hydrogen bonds
T/F: on the pH scale, a value of 1 is highly acidic, 14 is highly basic, and 7 is neutral.
T
T/F: the higher the concentration of hydrogen ions, the higher the pH.
F
T/F: in a polar covalent bond between two atoms, the shared electrons spend more time around the nucleus of one of the atoms than the other.
T
T/F: Ionic bonds are relatively strong in the presence of water.
F
T/F: electrons located in orbitals close to the nucleus of an atom have less potential energy than the electrons located in orbitals farther away from the nucleus.
T
A solution with a pH of 4.0 has _________ hydrogen ions as a solution with a pH of 2.0.
100 times less
Which functional groups are nonpolar?
CH3
Which functional group is an amino group?
NH2
Which functional groups are found in all amino acids?
NH2 & C=O-OH
What is the 3-D conformation assumed by a polypeptide chain?
Tertiary structure
The association of two or more polypeptide subunits to make a functional protein.
Quaternary structure
A prediction is?
an if-then statement
The dependent variable in an experiment is:
the stuff being measured
The independant variable in an experiment is:
the stuff being altered
A polar covalent bond is:
an unequal sharing of a pair of electrons by two atoms
T/F: The assembly of complex carbohydrates and proteins depends on condensation reactions.
T
T/F: The breakdown of some macromolecules depends on condensation reactions.
F
T/F: Condensation reactions use a molecule of water to separate a monomer from a polymer chain.
F
What kind of bonds hold the hydrogen atoms to the oxygen atom in a moleule of water?
polar covalent bonds
How many hydrogen atoms are present in a hydrocarbon chain of 8 carbons held together by 6 single covalent bonds and 1 double covalent bond?
16
A solution with a pH of 6 has _____ hydrogen ions as a solution with a pH of 3.
1000 times fewer
The lipid components of cellular membranes include ______
phospholipids and cholesterol
Integral membrane proteins are proteins that:
partially penetrate or completely span the phospholipid bilayer of the membrane.
Cells engulf particles and bring them into the cytoplasm using a process called _____
endocytosis
The movement of ions and other charged or large, polar molecules across biological membranes is made possible by _______
the integral membrane proteins present in the membrane.
What do gap junctions and desmosomes have in common with each other?
They both depend on the function of integral membrane proteins.
The unregulated movement of ions and large polar molecules across membranes is prevented by:
the hydrophobic core of the lipid bilayer
T/F: the rate of diffusion increases as temperature increases
T
T/F: Diffusion occurs whether or not a concentration gradient is present.
T
T/F: The rate of diffusion of a molecule depends on the kinetic energy of the molecule.
T
T/F: Diffusion refers to the tendency of molecules to move about randomly in space.
T
T/F: Net diffusion refers to the directional movement of molecules from an area of high concentration to one of lower concentration.
T
T/F: Net diffusion continues once a solution is at equilibrium.
F
T/F: Diffusion stops once a solution is at equilibrium.
F
Movement of substances across a membrane by active transport require what?
ATP and integral membrane proteins
A fatty acid with no double bonds between carbon atoms is _____ and has _______ hydrogen atoms bonded to the carbon atom.
saturated, the max number
The fluidity of cellular membranes is influenced by several factors including (3)
temperature, saturation of fatty acid side chains, and cholesterol
As the number of double bonds present in the fatty acide side chains of phospholipids increases, the fluidity of the membrane:
increases
Metabolic pathways that make simple molecules from complex ones are
catabolic
The types of reactions that take place in the pathways described in the question above are usually classified as ____ reactions because of their tendency to release energy.
Exergonic or spontaneous.
G=H-TS is the equation that describes Gibbs free energy. Rearranged, the equation can be written as H = G+TS. In either case, G stands for _____, H stands for ______, and S stands for ______.
usable (free) energy, total (enthalpy) energy, unavailable (entropy) energy
T/F Metabolic pathways always release energy stored in organic compounds
F
T/F: The product of one reaction becomes the substrate for the next reaction in a metabolic pathway.
T
T/F: Metabolic pathways are a series of enzyme catalyzed reactions.
T.
T/F: Metabolic pathways are similar in all organisms
T
T/F: Metabolic pathways are often compartmentalized in eukaryotic cells
T
Why do slight changes in pH dramatically decrease enzyme activity?
The hydrogen ions and ionic interactions that stabilize the conformation of the enzyme are disrupted.
What is a characteristic of the transmembrane protein of the protein (the part that resides in the phospholipid bilayer)
many of the amino acid side chains of the transmembrane domain are hydrophobic
The initial “investment” of energy required for a chemical reaction to proceed is called the:
activation energy
T/F: Enzyme substrates are guided into the active site by chaperone proteins
F
T/F: the supply of enzymes in a reaction is used up at the same rate as the other reactants.
F
T/F The active site of an enzyme is determined by the primary, secondary, and tertiary structure of the protein.
T
T/F: Enzymes with more than one polypeptide unit do not act as catalysts.
F
Some bacteria are metabolically active in hot springs because:
their enzymes have high optimal temperatures
The denaturation of an enzyme ocurs when: (3)
- the active site is destroyed
- the tertiary structure of the enzyme is altered
- environmental conditions deviate substantially from the enzymatic optimum conditions
Noncompetitive inhibition of enzyme activity is:
an example of allosteric regulation
Briefly describe the relationship between cellular respiration and photosynthesis.
photosynthesis stores energy in organic molecules and respiration releases it
The minimum requirements of photosynthesis are: (3)
light, CO2, H2O
Which of the steps of photosynthesis would be affected first by a lack of solar energy?
oxidation of chlorophyll
T/F: the electron transport chain in the cholorplasts of plant cells pumps hydrogen ions from the stroma into the thylakoid.
T
What happens to the stoma of chloroplasts in outdoor plants as the daylight fades into night?
the pH of the stroma decreases and becomes more acidic (aka the hydrogen ion concentration goes up)
What macromolecule is wood primarily made of?
carbohydrate
Where does the carbon in wood originally come from?
the air
Where did the energy released from a burning log originate?
Solar energy
Plasma membranes are found in:
animal, plant, and bacterial cells.
What outputs of photosynthesis are inputs of cellular respiration?
oxygen, carbon dioxide
T/F: The activity of DNA polymerase is higher in S phase of the cell cycle than it is in G1.
T
T/F: Each sister chromatid in a replicated chromosome is a double-stranded DNA molecule
T
T/F: A cell in G2 of the cell cycle has twice as many chromosomes as it had in G1
T
T/F: Following anaphase, a cell has half as much DNA as it did when it was in prophase.
F
T/F: A chromosome in G1 of the cell cycle is one double-stranded DNA molecule.
T
In plant cells, glycolysis takes place in the ______.
Cytoplasm
When a cell harvests energy stored in a molecule of glucose, it does so by _____.
removing electrons
When a cell metabolizes a glucose molecule, most of the energy is harvested in the ____
citric acid cycle
When oxygen is present, the pH in the matrix of the mitochondria should be _____ compared to the intermembrane space due to the _______ concentration of hydrogen ions in the intermembrane space.
higher/higher concentration
Most actively dividin cells in the body undergo mitotic division. The cell cycle in these cells is divided into two main parts which are ______ and _______
interphase and M phase (or mitotic phase)
Photosynthesis _______ energy while cellular respiration ________ energy.
stores (in organic molecules) , releases
What is the function of NADPH, NADH, and FADH2 in photosynthesis and respiration?
they transport high-energy electrons to an electron transport chain.
In the eukaryotic cells, complexes I, III, and IV are important components of the mitochondrial electron transport chain because during their reduction/oxidation cycles they pump _______ from the _______ to the _______.
hydrogen ions, matrix, intermembrane space
When oxygen is present and the citric acid cycle is active, the pH of the mitochondrial matrix is _____ than the intermembrane space because of the ________ concentration of hydrogen ions in the matrix.
higher (more basic), lower
The hydrogen ion gradient across the thylakoid membrane is required to _____
power ATP synthase
Describe the reducing agent in a redox reaction:
the reducing agent gets oxidized, loses an electron
In which compartment of the cell does the glucose convert to pyruvate in a redox reaction?
the cytoplasm
In which part of the cell does glycolysis take place?
Cytoplasm
In which part of the cell does ATP production by ATP synthase take place?
Inner mitochondrial membrane
In which part of the cell does the citric acid cycle take place?
matrix of the mitochondria
The products of glycolysis include (3):
ATP, NADH, and pyruvate
T/F: As a result of depletion of oxygen in the surrounding of the cell, the cell switches to anaerobic respiration to maintain some level of ATP production.
T
T/F: As a result of depletion of oxygen in the cell’s surroundings, Glycolysis, the citric acid cycle, and the electron transport chain, and ATP synthase all shut down due to lack of oxygen.
F
T/F When there is a lack of oxygen, fermentation pathways are activated and produce the same amount of ATP normally produced by glycolysis, the citric acid cycle, and the electron transport chain.
F
T/F: When oxygen is not present in a cell’s surroundings, cells use fermentation to regenerate the NAD+ needed for glycolysis.
T.
The mitochondrial electron transport chain is
a series of molecules including integral membrane proteins in the inner membrane of the mitochondria
The immediate energy source that directly powers ATP synthesis by ATP synthase in mitochondria is _____
the H+ gradient across the inner mitochondrial membrane
The thylakoid membranes in chloroplasts and the inner membrane of mitochondria are structurally and functionally alike because (2)
- both provide greatly amplified surface area for ATP production
- electron transport chains are found in both of them.
What would be most likely to act as an allosteric inhibitor of an enzyme that catalyed a reaction in the early pathway of glycolysis?
NAD+, NADPH, lactic acid, ATP, or oxygen?
ATP
ATP synthase is (3)?
- an enzyme
- a transport protein
- an integral membrane protein.
Describe the flow of ELECTRONS through living organisms.
water - photosynthesis - carbohydrate - cellular respiration -water
The two strands of a double-stranded DNA molecule are held together by ______ between nitrogenous bases and the nucleotides in each strand are held together by ______.
hydrogen bonds, covalent bonds
In DNA molecules, base pairs always include one purine and one pyrimidine. In the DNA of certain bacterial cells, 16% of the nucleotides are adenine. What are the percentages of the other nucleotides in the bacterial DNA?
16% Thymine, 34% Guanine, 34% cytosine
When a DNA molecule is heated, the two strands of the double helix become unzipped and come apart because the _____ between base pairs are destabilized.
hydrogen bonds
Most actively dividing cells in the body undergo mitotic cell division. The cell cycle in these cells is divided into two main parts which are _____ and ______.
interphase and M phase
All of the following happen during mitosis except:
condensing of the chromosomes
formation of the spindle microtubles
synthesis of DNA
uncoupling of the sister chromatids at the centromeres
synthesis of DNA
An epithelial cell divides during mitosis to form two genetically identical daughter cells. Prior to the mitotic phase of the cell, what must occur?
the nuclear envelope must disintegrate
the cell must first be fertilized
the nucleus must divide
chromatids must be separated
the cell must replicate its chromosomes
the cell must replicate its chromosomes
If a cell has defects in the function of its microtubules, which of the following would be most obviously affected?
mitosis
cytokinesis
G1
S phase
G2
mitosis
The muscle cells and nerve cells in a mouse look very different and serve very different functions in the mouse’s body. These differences are because the muscle cells and nerve cells in the mouse _______
express different genes
A gene is:
a region of DNA that is required for the production of an RNA molecule
The process of RNA synthesis by RNA polymerase using the information in a DNA molecule is called :
transcription
The promoter is a : amino acid or nucleotide/DNA ?
nucleotide/DNA
RNA polymerase is a: amino acid or nucleotide/DNA ?
amino acid
A transcription factor is a:amino acid or nucleotide/DNA ?
amino acid
the Transcription unit is a: amino acid or nucleotide/DNA ?
nucleotide/DNA
a polypeptide is a : amino acid or nucleotide/DNA ?
amino acid
the initiator site is a: amino acid or nucleotide/DNA ?
What describes the alleles of a particular gene if the phenotype of an individual that is heterozygous for that gene resembles neither parent?
one of the alleles is incomplete dominant over the other
Sister chromatids separate during:
meiosis II and mitosis!!!
Homologous chromosomes are separated during:
meiosis I (cytokinesis I)
The number of chromosomes is reduced by 50% during:
meiosis I
The muscle cell of a certain diploid organism has 12 chromosomes. How many copies of each gene are present in the cell at G1 of the cell cycle?
2
The muscle cell of a certain diploid organism has 12 chromosomes. How many copies of each gene is present in the cell at G2 of the cell cycle?
4
The muscle cell of a certain diploid organism has 12 chromosomes. How many molecules of DNA are present in the nucleus at G2?
24
The muscle cell of a certain diploid organism has 12 chromosomes. How many copies of each gene are present in the gamates of the organism?
1