exam 2 HW Q's Flashcards
Which component of a phospholipid is found in the interior of a lipid bilayer?
fatty acids
A protein on a cell surface that binds to a signaling molecule is an example of which of the following elements of cellular communication?
a receptor protein
Which of the following types of cellular activities can be a response to cell signaling?
Cell division is triggered
gene expression patterns are changed
enzyme activities are changed
cell signals are released to communicate with other cells
How does an ‘activated’ receptor transfer information into the cell?
through a conformational change of the receptor
On early earth, approximately 3.5 billion years ago: the first microbial mats (biofilm aggregations of prokaryotes) likely harvested energy through what?
redox reactions from chemicals found near hydrothermal vents.
Bacteria and Archaea generally can live…
in most environments on earth - including many regions with extreme conditions.
Unlike with animals, artifacts in the fossil record of bacteria and archaea offer very little information for analysis. Fossils of ancient prokaryotes look like tiny bubbles in rock.
How might scientists investigate their evolution and diversity in view of this challenge?
Scientists can make comparisons between DNA sequences in living bacteria and use this information to generate hypotheses about the organisms’ evolutionary relationships.
A theory that the complex eukaryotic cells of today arose through the combination of prokaryotic species into one.
Theory of Endosymbiosis
A type of cell that is lacking a nucleus or any other kind of membrane-bound organelle.
prokaryote
Evidence of earlier life on earth preserved in rock, dirt, or amber
fossil records
A type of cell containing a membrane-bound nucleus as well as other organelles.
Eukaryote
A small circular bit of DNA that is passed between bacteria during conjugation - allowing the exchange of genetic information.
Plasmid
Found in Eukaryotic cells, Examples include the nucleus, lysosome, mitochondria, and chloroplasts.
Membrane Bound Organelles
A type of prokaryote that generally reproduces asexually through binary fission, but can sometimes pass genetic information to other similar prokaryotes.
Bacteria
The process of genetic exchange in bacteria where one donor bacteria passes a plasmid to a recipient.
Bacterial conjugation
Membranes help the cell to maintain different concentrations of some substances on the two sides of the membrane. How could these ‘electrochemical gradients’ be used by the cell in practical ways?
Electrochemical gradients could be used to control the internal chemistry of the cell.
The electrochemical gradients could be harnessed work as a kind of battery for the cell.
Which of the following are parts of the endomembrane system?
The Endoplasmic reticulum
The Golgi Apparatus
The Lysosomes
What are 3 basic functions of membranes?
Act as a barrier to keep some compounds from moving in and out of the cell.
Be permeable in a selective way to receive or transmit certain compounds.
Receive and transmit signals from the environment to the interior of the cell.
What are 3 compounds found in cell membranes?
Phospholipids
Proteins
Cholesterol
Diffusion is an example of _____________ transport into the cell.
Passive
Which of the following components of the cytoskeleton are primarily utilized in cell motility and muscle contractions?
Actin
Cancer can arise from what
Homeostatic imbalances in cell function and failures in cell cycle checkpoints.
Over-active proto-oncogenes Underactive tumor suppressor genes
The cytoplasmic division of a cell at the end of mitosis or meiosis, bringing about the separation into two daughter cells.
Cytokinesis
The result of meiosis: a reproductive cell with a single set of unpaired chromosomes
Haploid Cells
The process of cell division resulting in the production of gametes.
Meiosis
The process of cell division resulting in diploid cells - occurring in the somatic cells of an organism’s body.
mitosis
The fusion of chromosomes at the start of meiosis.
Synapsis
Identical copies formed by the replication of a chromosome.
sister chromatin
If a haploid cell has n chromosomes, this type of cell has 2n chromosomes. Comprising the majority of your body cells.
diploid cells
The stage of meiosis where the chromosomes become visible and crossing over occurs.
ProphaseI
The transfer of signals across synapses between nerve cells is an example of ________________ signaling.
Paracrine
Which of the following human health disorders might be influenced by problems with cell to cell communication?
Diabetes
Cancer
Parkinson’s Disease
Would the influence of insulin (regulating cell’s response to glucose body-wide) be considered a paracrine factor or an endocrine factor?
Endocrine
When EGF (Epidermal Growth Factor) binds to EGFR (Epidermal Growth Factor Receptor), would this be considered the propagation of a signal or the response?
propagation
A form of signaling that acts locally between cells that are close neighbors.
Paracrine signaling
A form of communication where the cell acts locally by signaling to itself.
Autocrine signaling
A form of signaling that acts across long distances within the body of the organism. The ligands in these cases are called hormones.
Endocrine signaling
A form of communication between single-celled organisms - where if the population reaches a critical threshold, the whole group engages in a shared behavior.
Quorum sensing
A part of many signal transduction pathways where a series of kinase proteins transfer phosphate groups to molecules activating them.
phosphorylation cascade
The mechanism where a signal is transmitted into a cell and ultimately resulting in some change in gene expression.
signal transduction
A complex colony of bacteria and glycoproteins that can look rather slime-like.
biofilm
A form of paracrine signaling that is vital to the working of our nervous system - the connection point between two nerve cells.
Synapse
Which of the following is the likely origin of the chloroplasts of plants (as suggested by Lynn Margulis) and backed up by many supporting pieces of evidence?
Chloroplasts were originally free-living bacteria that have been incorporated into the cells of plants, a process called endosymbiosis.
What are the two most important products that result from photosynthesis (from an animal’s perspective)?
Oxygen and Sugars/Carbohydrates
- Which of the following structures in the chloroplast are where the Light-Dependent Reactions take place? 2. Where does the light-independent reaction (aka the Calvin Cycle) take place in the plant cell?
- The thylakoid membrane of the chloroplast
2. The stroma of the chloroplast
Which of the following is not used by both plants and cyanobacteria to perform photosynthesis?
Oxygen
What wavelength range of electromagnetic radiation can plants utilize to perform photosynthesis?
Between 400 and 700 nm
Why do plants have other photosynthetic pigments (such as Beta-carotene) in addition to chlorophyll?
Each type of pigment absorbs a different wavelength of light. By working with chlorophyll these other pigments help to capture the energy from a wider range of light.
What is the ultimate (original) source of the electrons for the chloroplast electron transpot chain?
H2O
According to the interview between Dr. Shaffer and Professor Kevin Redding, what can science tell us about the origins of the proteins that mediate oxidation-reduction reactions in photosynthesis?
The chemical pathways of photosynthesis were likely borrowed from other pre-photosynthetic organisms - which developed these pathways to capitalize on chemical gradient present on the early earth.
According to Professor Kevin Redding (in his interview with Dr. Shaffer), the function of the thylakoid membrane, stroma, and ATP synthase in chloroplasts can be compared to a:
water powered generator (at the base of a waterfall) with a solar pump bringing water back to the top of the hill.
What is the most important result of the Calvin Cycle?
The ‘fixing’ of CO2 to yield two molecules of PGAL.
The enzyme Rubisco is….
The most abundant protein (by weight) on earth
Capable of reacting with CO2 in the Calvin Cycle.
Capable of reacting with Oxygen in photorespiration.
Which part of the photosynthetic reactions would be affected if the cell could not produce RuBisCO?
Primarily the Light-Independent Reactions (Calvin Cycle)
The enzyme present in plant chloroplasts, involved in fixing atmospheric carbon dioxide during photosynthesis.
RuBisCO
The process of converting inorganic CO2 gas into organic compounds
Carbon Fixation
A green pigment, present in all green plants and in cyanobacteria, responsible for the absorption of light to provide energy for photosynthesis.
chlorophyll
The reactions of photosynthesis that convert carbon dioxide from the atmosphere into carbohydrates using the energy and reducing power of ATP and NADPH. Can occur in the absence of light.
Light-independent reaction
The range of wavelengths of electromagnetic radiation absorbed by a given substance.
Absorption Spectrum
A group of proteins, chlorophyll, and other pigments that are used in the light-dependent reactions of photosynthesis to absorb light energy and convert it into chemical energy.
photosystem
The first stage of photosynthesis where certain wavelengths of the visible light are absorbed to form two energy-carrying molecules (ATP and NADPH). Occurs in the thylakoid membrane in chloroplasts.
Light-dependent reaction
The organelle (derived from cyanobacteria) in plants where photosynthesis takes place.
chloroplast
Which of the following statements must be true in order for chloroplast ATP synthase to function properly?
The pH of the lumen must be lower than the stroma.
Which of the following statements BEST represents the relationship between cellular respiration and photosynthesis?
Photosynthesis stores energy in organic molecules, while respiration releases it.
Photosynthesis is the pathway used to synthesize carbohydrates from:
sunlight, carbon dioxide, and water
During photosynthesis in plants and algae, ____________ is oxidized and ______________ is reduced.
H2O; CO2
The pH in the stroma of the chloroplast should be ____________ compared with the thylakoid lumen due to the ___________ concentration of protons in the thylakoid lumen.
higher; higher
If plants are exposed to a toxin that makes the thylakoid membrane leaky to protons, predict the rate of ATP production by the plants.
ATP production will decrease.
Which of the following DNA molecules would be more stable under conditions of increasing temperature?
A DNA molecule that has more guanine and cytosine nucleotides
The discovery that DNA from killed virulent bacterial can transform live harmless bacteria into virulent forms means that DNA:
contains information that controls an organism’s traits.
The central dogma of molecular biology states that information flows from:
DNA to RNA to protein.
In prokaryotes, newly synthesized proteins are found in the _____ and DNA are observed in the _____.
cytoplasm; cytoplasm
Imagine you have discovered a new species of bacteria. To begin your investigation of this organism, you run an assay on the total nucleotide content of the bacterial DNA. If the cytosine content of DNA from the bacterial cells is 40%, what is the adenine content?
10%
Which one of the following represents an actual Watson-Crick base pair with the LARGEST number of hydrogen bonds?
cytosine and guanine
Which one of the following activities would LEAST likely be found in a topoisomerase?
adding nucleotides to the end of a DNA strand
The strands in a double helix of DNA are:
antiparallel.
complementary.
held together via hydrogen bonds.
wound around each other with 10 base pairs per turn.
DNA is usually a _____-stranded molecule, and RNA is usually ______-stranded.
double; single
What is Uracil ONLY present in
RNA
Is RNA a long term storage molecule of genetic information?
NOOO
what are 3 processes RNA is involved in
transcription, translation, and splicing
A template DNA strand contains the sequence 5’-ATGCTGAC-3’. The corresponding sequence in the RNA transcript is:
A. 5’-TACGACTG-3’.
B. 5’-GTCAGCAT-3’.
C. 5’-UACGACUG-3’.
D. 5’-GUCAGCAU-3’.
D
Transcription of RNA from DNA in eukaryotes requires what 4 things
transcription factors.
activator proteins.
a promoter sequence.
RNA polymerase.
Which of the following brings amino acids to the ribosome for use in translation?
tRNA
The function of a protein is dependent upon the shape into which the chain of amino acids folds. Many noncovalent interactions are responsible for maintaining the protein’s shape. Assume you have isolated a protein from an organism in its proper shape, and you have treated it with an enzyme that selectively targets and breaks only the peptide bonds in the proteins. Would the protein retain its shape under these conditions?
No; while the noncovalent bonds determine the shape of a protein, the peptide bonds are required to hold the amino acids together.
Select the level of protein structure that applies in each case.
“Hydrogen bonds between peptide backbone components form a distinct helical structure.”
secondary
Select the level of protein structure that applies in each case.
“Hydrogen bonds between peptide ‘backbone’ components on one polypeptide and R groups on another polypeptide contribute to the overall function.”
quaternary
Select the level of protein structure that applies in each case.
“Peptide bonds form between the monomer amino acids.”
primary
Which one of the following can contribute to a protein’s tertiary structure?
ionic bonding
van der Waal’s forces
covalent bonding
hydrogen bonding
all of the above
Use the double-stranded DNA molecule below to answer the following questions. The first pair of nucleotides (bolded) contains the start point of transcription (proceeding from left to right).
5’-ATGTCAGGTACGCCACAT-3’
3’-TACAGTCCATGCGGTGTA-5’
Which of the following is the correct mRNA produced from the transcription of this DNA molecule?
5’-AUGUCAGGUACGCCACAU-3’
Which of the following occurs in the A site of the ribosome during translation?
An incoming charged tRNA binds to this site.
A consecutive sequence of codons following a start codon is called a:
reading frame
Amino acid sequences evolve through:
mutation and selection
On the lagging strand, DNA is synthesized in short stretches, each of which is initiated by a separate primer. When the replication fork reaches the end of the linear chromosome, there is no place for a primer to be made for the DNA fragment to be copied at the end of the chromosome. These ends thus remain unpaired, and over time these ends may get progressively shorter as cells continue to divide. The enzyme _______________ helps to repair this shortening of the end of the chromosome.
Telomerase
What kind of enzyme is primase?
DNA-dependent RNA polymerase
Which of the following components is not involved during the formation of the replication fork?
Ligase
_________ signals are produced by the target cell that stay within the target cell.
Intracrine
________ signals target adjacent (touching) cells.
juxtacrine
chemicals capable of acting like hormones outside the body of the secreting individual, to impact the behavior of the receiving individuals.
pheromones
