BIO 311C Squarecap questions for Exam 2

If the dimension of a cube shape cell is 10 µm, the ratio of cell surface area to volume would be _____ to 1.

0.6

Three essential requirements for an ancestral cell to grow and multiply are 1. ____________________to define the cell and contain reactions within 2. ___________________ make and break molecules and 3. ___________________ material to replicate & reproduce.

1. Cell membrane 2. Enzymes or metabolism 3. Genetic material

A paleontologist estimates that when a particular rock formed, it contained 12 mg of the radioactive isotope potassium-40, which has a half-life of 1.26 billion years. The rock now contains 3 mg of the isotope. About how old is the rock? Enter in billions of years.

2.52 Since the amount is halved twice (12 to 6 and then to 3 mg), it took 2 half lives to reach there. Hence 2 x 1.26 = 2.52 billion years.

How many different types of ribosomes are found in a plant cell? Hint: consider the various locations of the plant genome.

3

If the dimension of a cube shape cell is 1 µm, the ratio of cell surface area to volume would be _____ to 1.

6

How many cellular structures the rough endoplasmic reticulum is associated with?

8

Both mitochondria and chloroplast are maternally inherited. Some plants develop resistance to atrazine herbicide through a mutation of a gene located in the chloroplast. If male plants without any such herbicide resistance are crossed with an atrazine resistant female plant, what will be the resistance level of offspring plants? A) All offspring will be resistant. B) None of them will be resistant. C) Half will be resistant and half susceptible. D) Only the female plants will be resistant and not the male plants. E) Only the male plants will be resistant and not the female.

A) All offspring will be resistant. Since mitochondria and chloroplasts are only inherited from the mother, all offspring will have the genes located on those organelles.

Which of the following is the most rapidly reproducing organisms, based on their simplicity or complexity? chart: https://docs.google.com/spreadsheets/d/1O6Mhhxrn-BWz2DaqMfJerfq17lEP9h-U1m4waaV6NdY/edit?usp=sharing A) Bacteria only B) Archaea only C) Eukarya only D) A and B are possible E) None of these

A) Bacteria only

You have isolated some organisms that are unicellular with cell wall containing peptidoglycan and have flagella without any membrane enclosure. Which group do these organisms belong to? chart: https://docs.google.com/spreadsheets/d/1O6Mhhxrn-BWz2DaqMfJerfq17lEP9h-U1m4waaV6NdY/edit?usp=sharing A) Bacteria only B) Archaea only C) Eukarya only D) A and B are possible E) None of these

A) Bacteria only

Which of the following molecules do not have any charges on them so that they cannot be separated by gel electrophoresis? There may be more than one answer. A) Carbohydrates B) Trigylcerides C) Proteins D) DNA E) RNA

A) Carbohydrates B) Trigylcerides

You would be wasting your time if you were trying to use a light microscope to see_______ A) ribosomes B) animal cells C) bacteria D) yeast cells E) chloroplasts

A) ribosomes

You are working for CDC and investigating a toxic E. coli contamination in lettuce. Which method would be useful to identify toxic E. coli?

A. Microscopes can be used only to detect if any bacterial contamination is present and not if they are toxic or not. B. Isolating and culturing such bacteria and looking for some markers will identify if they are toxic or not.

When the pH was increased from 5 to 7 in an in vitro experiment, these structures purified from animal cells stopped digesting their contents. What are these structures? A) smooth ER B) lysosomes C) nucleus D) mitochondria E) Golgi vesicles

B) lysosomes Contain hydrolytic enzymes that digest macromolecules (need acidic environment). These enzymes are active at pH 5, but are inactive if the pH is raised to 7.

Which of the following action facilitated by microfilaments, a plant cell will not be able to do? A) Movement of chromosomes during cell division B) Transport of vesicles along microtubules C) Cleavage furrow (pinching in middle of cell) formation during cell division D) Cytoplasmic streaming of chloroplasts E) Synthesis of carbohydrates and essential amino acids

C) Cleavage furrow (pinching in middle of cell) formation during cell division The tough cell wall prevents cells from cleaving.

Which organisms will have linear chromosomes with histone proteins bound to their DNA? chart: https://docs.google.com/spreadsheets/d/1O6Mhhxrn-BWz2DaqMfJerfq17lEP9h-U1m4waaV6NdY/edit?usp=sharing A) Bacteria only B) Archaea only C) Eukarya only D) A and B are possible E) None of these

C) Eukarya only

Which of the following is the correct sequence of plant cell structural layers, beginning with the cytoplasmic side and progressing outward? It may help to draw two adjacent plant cells and the cell walls to answer this question. A) Plasma membrane, middle lamella, secondary wall, primary wall B) Middle lamella, primary wall, secondary wall, plasma membrane, C) Plasma membrane, secondary wall, primary wall, middle lamella D) Primary wall, middle lamella, secondary wall, plasma membrane, E) Plasma membrane, secondary wall, middle lamella, primary wall

C) Plasma membrane, secondary wall, primary wall, middle lamella

What structures are similar to each other in the list given below? A) Tight junctions and primary cell wall B) Secondary cell wall and anchoring junctions C) Plasmadesmata and gap junctions D) Middle lamella and anchoring junctions E) Gap junctions and secondary cell wall

C) Plasmadesmata and gap junctions

If you were to genetically engineer a papaya plant that will resist fungal disease, you would like to express high levels of the enzyme _____________ that will degrade the fungal cell wall. A) proteinase B) phosphatase C) chitinase D) cellulase E) lysozyme

C) chitinase

Which of the following structures are important for providing energy for cytoplasmic functions in a plant? A) microtubules B) chloroplast C) mitochondrion D) lysosome E) nucleus

C) mitochondrion

Arrange the following processes in the order in which they evolved from oldest to latest. 1. Photosynthesis 2. Respiration 3. Neuron signaling A) 1, 2, 3 B) 1, 3, 2 C) 3, 2, 1 D) 2, 1, 3 E) 2, 3, 1

D) 2, 1, 3 Respiration is a property of all living organisms including bacteria - the oldest life form, followed by photosynthesis common in cyanobacteria & plants and the nervous system is common in animals which eveloved last.

Arrange the following sequence of procedures in the proper order in this experiment done to determine proteins present in pea plants during germination. 1. Load the proteins in polyacrylamide gel electrophoresis and separate them 2. Break the cells by grinding them in liquid nitrogen and suspending in a buffer 3. Select a suitable tissue to isolate proteins expressed only during germination 4. Centrifuge the broken cells to purify proteins from other molecules A) 1,3,2,4 B) 3,2,1,4 C) 2,4,1,3 D) 3,2,4,1 E) 2,4,3,1

D) 3,2,4,1

Cell Theory in its modern form includes all of the following postulates except __________________ A) All organisms are composed of one or more cells. B) Cells are the smallest living things. C) Cells arise only by division of a previously existing cell. D) All cells contain nucleus E) Cell is the unit of life.

D) All cells contain nucleus

Fresh water protists such as paramecium maintain homeostasis of its salt concentration by pumping water out of the cell. Which of the following structures would serve this purpose? A) Large central vacuole B) Small central vacuole C) Proton pump D) Contractile vacuole E) Food vesicle

D) Contractile vacuole In fresh water protists, helps remove excess water

Which of the following is the correct sequence of events in the origin of life? I. Synthesis of organic monomers II. Formation of prebiotic structures III. Synthesis of organic polymers IV. Formation of reproducible cells A) III, II, I, IV B) I, II, IV, III C) IV, III, I, II D) I, III, II, IV E) II, III, I , IV

D) I, III, II, IV Monomers can form polymers which are required for prebiotic structures. Reproducible cells are highly complex and come last in the sequence of events.

Which of the following is the right order of evolution of the following organisms? I) Plants II) Rodents III) Humans IV) Bacteria A) II, III, IV, I B) I, IV, II, III C) IV, II, I, III D) IV, I, II, III E) IV, III, I, II

D) IV, I, II, III

How does the double membrane structure of mitochondrion help in its function to make ATP? A) Stopping any molecules to go through mitochondrion B) Allowing only small molecules to go through the double membrane C) Controlling only polar molecules to go through D) Maintaining conditions within and between the two membranes to allow ATP synthesis E) Allowing only non-polar molecules to go through them

D) Maintaining conditions within and between the two membranes to allow ATP synthesis The pH of the mitochondria is very important for ATP synthesis and internal and external conditions need to be monitored closely for optimal functioning.

Which of the following is not a common feature of both chloroplast and mitochondrion? A) Have their own DNA B) Make ATP C) Prokaryotic in nature D) Makes essential amino acids

D) Makes essential amino acids Essential amino acids are made only by chloroplasts as we need to consume them in our diet.

Tasmanian tigers are extinct because of hunting by humans but the close relative Tasmanian devils are still alive and thriving well. If you were to use an adult cell's nucleus with intact DNA from a Tasmanian tiger to replace the nucleus of a Tasmanian devil's egg cell and make it produce to a new organism in a surrogate Tasmanian devils womb, what kind of organism will it make? A) Completely Tasmanian Tiger B) Completely Tasmanian Devil C) A hybrid with 50% of both organisms D) Mostly Tasmanian Tiger with the mitochondrial DNA from the T. Devil E) Mostly Tasmanian Devil with the mitochondrial DNA from T. Tiger

D) Mostly Tasmanian Tiger with the mitochondrial DNA from the T. Devil The mitochondrial DNA is maternally inherited as it will come with the egg cell.

We need to consume essential amino acids in our diet because we do not have ______________ that make essential amino acids. A) Mitochondria B) Ribosomes C) Lysosomes D) Plastids E) Glyoxysomes

D) Plastids Plastids include chloroplasts, leucoplasts which make essential amino acids.

Which of the following statements is/are true about the origin of life on earth? A) All life forms were created by some superhuman powers B) Life started with aliens spaceship bringing the first life forms C) Water bubbles in the air combined with minerals and formed life D) Simple molecules combined to make larger molecules and eventually the ancestral cells E) All life forms existed as it is present today ever since the earth was formed

D) Simple molecules combined to make larger molecules and eventually the ancestral cells Chemical evolution of first life forms from basic molecules is the most plausible way. Some steps of this process has been proven by scientific experiments.

The digestive tract lining contains epithelial (outer lining) cells that do not allow food particles to randomly go inside the body except through specific proteins on their cell membrane. Which of the following structure blocks random diffusion of food particles between epithelial cells? A) Desmosomes B) Gap junctions C) Plasmodesmata D) Tight junctions E) Cell wall

D) Tight junctions

What are the barriers for glucose to enter a bacterial cell from the medium? A) plasmamembrane --> cell wall --> capsule B) plasmamembrane --> capsule -->cell wall C) capsule --> plasmamembrane --> cell wall D) capsule --> cell wall --> plasmamembrane E) cell wall --> capsule --> plasmamembrane

D) capsule --> cell wall --> plasmamembrane

Read this paragraph and answer the question CYP3A4 is a member of the cytochrome P450 superfamily of enzymes. The cytochrome P450 proteins are monooxygenases that catalyze many reactions involved in drug metabolism and synthesis of cholesterol, steroids, and other lipids components. The CYP3A4 protein localizes to the endoplasmic reticulum, and its expression is induced by glucocorticoids and some pharmacological agents. Cytochrome P450 enzymes metabolize approximately 60% of prescribed drugs, with CYP3A4 responsible for about half of this metabolism; substrates include acetaminophen, codeine, ciclosporin (cyclosporin), diazepam, and erythromycin. The enzyme also metabolizes some steroids and carcinogens. Most drugs undergo deactivation by CYP3A4, either directly or by facilitated excretion from the body. If someone is addicted to Oxycontin, shown below, which of the following enzymes and structures would try to detoxify them? image: https://sqrcp.imgix.net/6f312462-12f5-11e8-a919-0242ac120004 A) cytochrome p450, lysosomes B) cytochrome p450, rough ER C) lysoszyme, mitochondrion D) cytochrome p450, smooth ER E) lysozyme, smooth ER

D) cytochrome p450, smooth ER Responsible for chemical detoxification among other functions

The major differences in the function of rough ER compared to smooth ER is to __________________ A) make steroid hormones B) synthesize phospholipids C) detox drugs D) make proteins E) make carbohydrates

D) make proteins Rough ER has ribosomes attached to them and they make proteins that are bound for membrane or secretion.

In agarose gel electrophoresis, DNA or RNA fragments migrate towards ___________ end of the gel plate because of their____________. A) the neutral..... charge B) the anode ..... size C) the cathode ..... charge D) the anode ..... charge E) the neutral ..... size

D) the anode ..... charge

Which of the following structures are important for maintaining water pressure and movement of water in a tall plant? A) Desmosomes B) Plasma membrane C) Plasmodesmata D) Tight junctions E) Cell wall

E) Cell wall

What will happen if the segment of DNA coding for target sequence is deleted from a gene encoding a protein located in lysosomes? A) Its mRNA will not be made in nucleus. B) Its mRNA will not be processed properly. C) Protein synthesis will not happen for this mRNA. D) Once the protein is made, it will return to nucleus. E) It will not reach the target site, lysosome.

E) It will not reach the target site, lysosome. Target sequence is only one part of the protein and its absence will not allow the protein to reach its target, Lysosome.

Which of the following pathway is the most probable pathway for secretory proteins that is glycosylated along the way? A) ER → Vesicle → nucleus → lysosomes → plasma membrane B) Nucleus → Smooth ER → Golgi apparatus → plasma membrane C) Golgi Apparatus → vesicles → lysosomes → plasma membrane D) Ribosomes → lysosomes → Golgi apparatus → plasma membrane E) Rough ER → vesicles → Golgi apparatus → plasma membrane

E) Rough ER → vesicles → Golgi apparatus → plasma membrane Rough ER makes the protein, packages them into vesicles and the Golgi modifies the proteins and makes sure they are sent tot he plasma membrane for secretion

What are some of the good pieces of evidence to understand evolution?

RNA and DNA

Bacteria and fungi can degrade wood because they can make the enzyme _________________________.

cellulase

Read the following abstract and answer what type of information is/are needed for a protein to reach its destination within the cell. Protein targeting to subcellular organelles via mRNA localization☆ Authored by Benjamin L.WeisaEnricoSchleiffabWilliamZergesc 2012 Cells have complex membranous organelles for the compartmentalization and regulation of most intracellular processes. Organelle biogenesis and maintenance requires newly synthesized proteins, each of which needs to go from the ribosome translating its mRNA to the correct membrane for insertion or translocation to an organellar subcompartment. Decades of research have revealed how proteins are targeted to the correct organelle and translocated across one or more organelle membranes to the compartment where they function. The paradigm examples involve interactions between a peptide sequence in the protein, localization factors, and various membrane-embedded translocation machinery. Membrane translocation is either cotranslational or posttranslational depending on the protein and target organelle. Meanwhile, research in embryos, neurons, and yeast revealed an alternative targeting mechanism in which the mRNA is localized and only then translated to synthesize the protein in the correct location. In these cases, the targeting information is encoded by cis-acting sequences in the mRNA ("Zipcodes") that interact with localization factors and, in many cases, are transported by molecular motors on cytoskeletal filaments. Recently, evidence has been found for this "mRNA-based" mechanism in organelle protein targeting to the endoplasmic reticulum, mitochondria, and the photosynthetic membranes within chloroplasts.

mRNA sequences

How does a larger cell compensate for the reduced amount of surface area as the cell volume increases?

membrane folds and compartments

Give an example of how cytoskeletal elements helps in sexual reproduction of animals.

movement of egg cells and sperm cells

Read the following paragraph from https://ghr.nlm.nih.gov/mitochondrial-dna and answer. What types of symptoms would show in an individual with a defective mitochondrial genes? Mitochondria are structures within cells that convert the energy from food into a form that cells can use. Each cell contains hundreds to thousands of mitochondria, which are located in the fluid that surrounds the nucleus (the cytoplasm). Although most DNA is packaged in chromosomes within the nucleus, mitochondria also have a small amount of their own DNA. This genetic material is known as mitochondrial DNA or mtDNA. In humans, mitochondrial DNA spans about 16,500 DNA building blocks (base pairs), representing a small fraction of the total DNA in cells. Mitochondrial DNA contains 37 genes, all of which are essential for normal mitochondrial function. Thirteen of these genes provide instructions for making enzymes involved in oxidative phosphorylation. Oxidative phosphorylation is a process that uses oxygen and simple sugars to create adenosine triphosphate (ATP), the cell's main energy source. The remaining genes provide instructions for making molecules called transfer RNA (tRNA) and ribosomal RNA (rRNA), which are chemical cousins of DNA. These types of RNA help assemble protein building blocks (amino acids) into functioning proteins.

no energy

RNA considered being the first genetic material formed even before DNA because it can _________________ and ___________________________ (2 or 3 words in each space)

store information and act as enzymes

While you swim in the pool, you do not absorb water and swell because the skin has_________________________.

tight junctions and selective permeability