Test 1 - Chapters 1-4 Flashcards
Why are enzymes highly sensitive to ph and temperature?
because changes in temperature and pH can break hydrogen bonds and thus alter the enzyme shape.
Why is DNA different than RNA
DNA encodes hereditary information, whereas RNA is an intermediate in information transfer.
Myoglobin, an oxygen binding protein, has quaternary structure, implying that it has what?
At least two different protein subunits
Most enzymes are
Proteins
The enzyme sucrase increases the rate at which sucrose breaks down int glucose and fructose by doing what?
Lowering the activation energy of the reaction
Negative Feedback mechanisms are
important for homeostasis
Enzymatic reactions can become saturated as substrate concentration increases because:
There are a limited number of the enzyme molecules present
Two complementary strands of DNA are held together by
Hydrogen bonding
The process by which a final product inhibits the enzyme that catalyzes the commitment step in a metabolic pathway is called
Feedback inhibition
A typical carbon atom has 6 protons in the nucleus and four electrons in the outer orbital. Oxygen has:
8 protons in the nucleus and 6 electrons in the outer orbital
The active site of an enzyme is:
Specific for the substrates
Evidence indicates that all life on Earth today
Has a single common ancestor
Cells:
Can be building blocks for complex organisms
Genes are:
Sequences of DNA that code for proteins
What is a characteristic that is the same in liver cells and brain cells
Genome
The nucleus of animal cells:
Contains DNA packaged with several proteins
what is the correct sequence, from weakest to strongest, of atomic interaction strength
Van der waals -> hydrogen -> ionic -> covalent
Table salt, NaCl, is electrostatically neutral. What does it do when it dissolves in water?
Dissociates to form Na+ and Cl- ions that interact with water molecules.
The _____ “building blocks” of proteins become _____ are the polymer is formed
amino acid; covalently bonded
The ____ characteristic of phospholipids refers to them having both polar regions and non-polar regions
amphipathic
RNA translation occurs
at the ribosomes
The Na+K+ATPase is an _______ that uses up to 40% of the ATP produced in a cell to achieve _____
enzyme; primary active transport
Prokaryotes
are surrounded by a cell membrane
The hypothalamic-pituitary-gonadal axis orchestrates the reproductive system, and its hormone levels are subject to negative feedback regulation via:
steroid-hormone receptors in the hypothalamus and pituitary
The enzyme alcohol dehydrogenase increases the rate at which acetaldehyde is converted to ethanol. As the concentration of acetaldehyde is increased, the rate of conversion speeds up, but eventually reaches a maximum, at which point further increases in the concentration of acetaldehyde have no effect, this maximum rate is due to:
The number of available alcohol dehydrogenase enzymes.
During diffusion of a solute, the molecules more from ____ concentration to _____ concentration.
high;low
If the diameter of a cell is increased, the ratio of surface are to volume
decreases
Carbon to carbon double bonds are found in
unsaturated fatty acids
competitive inhibitors of enzymes work by:
binding to the active site
The mitochondria are responsible for
ATP synthesis
Replication is the synthesis of _____ and transcription is the synthesis of _____
an identical copy of DNA; RNA based on the DNA template
“essential” amino acids refer to amino acids that
Must be eaten as part of a diet
Most of the water in your body is located in your
Cells
As sodium (Na) and chloride (Cl) interact, Na is likely to ____ an electron while Cl is likely to ____ an electron.
lose;gain
For two atoms of different electronegativity values
The atom with the lower electronegativity is less likely to form a hydrogen bond
A characteristic of phospholipids that allows them to form a bilayer is the presence of
hydrophobic fatty acid tails
Anabolic and catabolic reactions are often linked. For example, the breakdown of carbohydrates could be linked to the:
anabolism of lipids
Corals without any symbiotic algae are
animals
Protein interactions underlie the amoeboid movement we saw in class, as we watched the amoeba
engulf its prey
What is the correct sequence of reactions in (aerobic metabolism)
glycolysis –>pyruvate transition –> citric acid cycle
Adenosine is the normal ____ for its membrane receptor
ligand
The concentration of hydrogen ions in mitochondria is maintained by
electron transport and proton pumping
Most ATP produced in our bodies is synthesized directly by:
ATP Synthase
Where is the oxygen gas produced during photosynthesis derived from?
water
The light reactions of photosynthesis provide the Calvin cycle with
ATP and NADPH
When insulin binds to receptor proteins on its target cells, the cells will
increase the number of glucose-transporter proteins on the membrane
How are receptor proteins and enzymes similar
both can be “saturated” when excess ligands are present
Catabolic and anabolic reactions are often linked to allow one to drive the other. For example, the synthesis(i.e. anabolism/build up) of lipids could be linked to the
catabolism(break down) of carbohydrates
An excess of what can interfere with and/or stop the calvin cycle
oxygen
What is the process that uses light energy to extract hydrogen atoms from water?
photosynthesis
which biological group is dependent on photosynthesis for its survival
nearly all organisms depend on photosynthesis
The energy difference between an electron excited by a photon compared to when the electron was in its ground state is ____ of the photon
related to the wavelength
In noncyclic photophosphorylation, electrons from water end p in
NADPH *
*NADPH is an electron carrier
Most of the lipids that make up biological membranes are called
phospholipids
High hydrogen atoms means
low PH
low hydrogen atoms means
high PH
The storm of the chloroplast is the place where
the highest PH is found
The synthesis of one glucose molecule in the Calvin cycle uses
way more ATP and NADPH than in the other choices
other choices were:
2 ATP 4 NADH
4 ATP 2 NADH
6 ATP 2 NADH
Agonists activate metabolic and biochemical pathways and antagonists block responses. Caffeine is a stimulant that works because it acts as a(n) _____ to the adenosine receptors in a person’s brain.
competitive antagonist
Yeast cells tend to create anaerobic conditions and therefore you would expect that they are able to
Produce ethanol
What process(es) favor the persistence of the concentration gradient for glucose across the membranes of muscles
glycolysis
synthesis of glycogen
carbohydrate catabolism
Pyruvate oxidation (pyruvate transition) step for one pyruvate molecule leads to the direct formation of
Acetyl-CoA
NADH
Co2
What is the role of oxygen in human cells
to accept electrons from the respiratory chain
The role of oxygen in chloroplasts is
limited to being a byproduct
-chloroplasts are the location of photosynthesis ..photosynthesis produces O2 and uses CO2
How do competitive inhibitors of enzymes and most antagonists of cell signals (i.e. caffeine) work
by fitting into the active site of the affected protein
ligand-receptor interactions differ from enzyme-substrate reactions in that
the ligand signal is not usually metabolized into reaction products
The complete catabolism of 2 molecules of glucose produces ____ ATP produced by the process of oxidative phosphorylation. (Do not subtract any ATP “used up” in these reactions)
68
In simple diffusion
the rate of transport is independent of the concentration of the molecule transported
*was thrown out on test
This part of metabolism produces the most ATP per molecule of glucose used
The electron transport chain
Compared to fermentation, the aerobic pathways of glucose metabolism produce:
more ATP
What part of the phospholipid bilayer blocks the simple diffusion of glucose across membranes
lipid
Many membrane spanning proteins include portions that extend both outside and inside the cell; the amino acid side chains (R groups) in the middle of the membrane are most likely going to be
hydrophobic
In both plants and animals the energy transfers accompanying the movement of hydrogen ions down the hydrogen-ion gradient are most closely linked to
ATP- synthase
When a mouse cell and a human cell are fused together in an experiment, the membrane proteins of the two cells become uniformly distributed over the surface of the hybrid cell. This occurs because:
many proteins can move around within the bilayer
a “double set” of membranes is a characteristic of the:
mitochondrion, chloroplast, nucleus
The adjacent cells in a human’s heart are strongly held together by…
desmosomes
Normal red blood cells placed in a hypertonic saline solution would
lose water and shrink
what are ribosomes composed of
rRNA and proteins
a diploid cell is a cell:
with pairs of each chromosome
during the cell cycle, for most cells, most time is spent in
interphase
during the cell cycle, for most cells, the chromosome condense and first appear as paired chromatids in
prophase
stretched out in a linear fashion, the length of human DNA is about _____. a typical cell’s diameter is about ____.
2 meters; 10 micrometers
in animals cells, separation of daughter cells is completed by the actions of the
contractile ring
In a diploid organism with 23 pairs of chromosomes, there are ____ chromosomes in each gamete cell
23
RNA splicing
removes introns and attaches together the exons
The two anti-parallel strands of double-stranded DNA associate with each other because of
hydrogen bonds
This compound is composed of amino acids that have been covalently bonded together
insulin
Base-pairing between complementary bases is an essential feature of
DNA replication
Transcription
& Translation
Choose the ingredient used in transcription but not in DNA replication
UTP (uracil)
Identify the transcription factor that regulates certain patterns of gene expression
estrogen and its receptor
In the life cycles of kangaroos and all other marsupials, diploidy is first seen at
fertilization
Changes in covalent bonds during post-translation modification of newly synthesized proteins includes:
phosphorylation, proteolysis, glycosylation
The elongation of a nucleotide sequence during DNA replication
occurs with ATP hydrolysis needed to drive covalent bonding
With ____ of DNA polymerase activity, the replication of 4.6 million base pairs of DNA in E. Coli is complete in ______
10,000 points; 40 minutes
Choose the reproductive modality with the longest evolutionary record of success
binary fission
Okazaki fragments are needed during
DNA production on only the lagging strand
A double-stranded DNA molecule with 35% thymine, must contain ___% guanine
15
Based on a template strand of DNA that has 35% adenine, the RNA transcript must contain
35% uracil
Choose the strand that is complementary to this DNA sequence 5’ -ATTCCG- 3’
5’ -CGGAAT- 3’
Choose the best molecular model describing the structure of the DNA molecule in prokaryotes
helical, double stranded, and anti-parallel
RNA polymerase is a
protein
In eukaryotes, exons are:
spliced together from the original transcript
in prokaryotes, the ribosomes are the
site of translation
An mRNA molecule with 360 codons has ___nucleotides
1,080
Modification of chromatin is responsible for
chemical modification of histones
epigenetic changes in gene expression
&differential access of RNA-polymerase to genes
A “calico cat” is most likely ___ and the varied color pattern arises from ____.
a female; random X-inactivation
“start” and “stop” codons ____ on the protein
differ in that only “start” codons determine an amino acid
In a vertebrate, the amount of production of beta-globin varies tremendously among different cell types. This is because:
different cell types have different transcription factors
A major biological advantage of binary fission over sexual reproduction is that binary fission
more quickly makes “clones” when conditions are good for growth
DNA molecules placed in a ge where an electrical gradient is applied will
move toward the region of positive charge
A transcription factor is _____ that alters transcription by binding to_____
a protein; the promoter
Choose the codon that will bind the anticodon 3’-AUC-5’
5’-UAG-3’
The one-gene = one protein idea grew from this scientist’s research on alkaptonuria, a congenital disease
Sir archibald Garrod
Choose the type of molecule that is needed to transfer information from mRNA
tRNA
Choose the protein that is cut from a larger protein before becoming a signal
insulin
When glucose and lactose are both abundant, is it likely that E. Coli will express genes to metabolize lactose?
No, because lactose is broken down into glucose, which is already abundant
In eukaryotes, a promoter is the region of the
DNA that binds RNA polymerase
In a fly, the transcription rates of a gene that codes for an enzyme vary tremendously among different cell types. The most likely reason for these differences is that different cell types have different
transcription factors present
The coordinated multi-protein response of plants to drought stress is an example of ___ in operation
coordinated gene expression
A bacterial gene (gene M) ordinarily makes a protein that binds to DNA, but a mutation of gene M leads to an increase in the expression of gene Q. We can conclude that:
gene M is a negative regulator of gene Q
