Exam questions review Flashcards
This characteristic corresponds to which bryophyte group:
The sporophyte is an orange filament growing above the protonema.
Mosses.
This characteristic corresponds to which bryophyte group:
All of them have stomata.
Hornworts
This characteristic corresponds to which bryophyte group:
They likely are the first plant group to have evolved.
Liverworts
In bryophytes, which process produces spores?
Meiosis
Which of the following is not a characteristic shared by all land plants?
a. A sessile lifestyle.
b. A multicellular haploid stage
c. Storing energy as starch.
d. A cell wall made of cellulose
e. Diploid tissue surrounding the zygote
e. Diploid tissue surrounding the zygote.
With the Earth being approximately 4.5 billion years old, why did land plants evolve only 500 million years ago and not before?
Because before that, there was nothing to protect living organisms from the sun’s damaging radiation.
In mosses, which generation is shorter-lived than the other?
The sporophyte generation
True or false: Ferns and their relatives produce gametes using mitosis.
True.
Which appropriate plants would be seen in the Devonian period?
Flowers.
Why did the transition from water to land come earlier in plants than in animals?
Because by being photoautotrophs, plants were able to colonize bare land. On bare land, there is no food source for heterotrophs. Only photoautotrophs would be able to get energy to grow.
The earliest fossil of a deuterostome is dated to approximately 540 millions years ago. If this is compatible with the theory of evolution, the animal must have
Lived where?
Had what type of cleavage?
Lived in water.
Had radial cleavage.
Why were prehistoric lycophytes able to reach 20-30 meters in size then, and not now?
Because back in the days, lycophytes had the most advanced vascular system; they were the ones that were able to grow faster and reach light more easily.
True or false: the diploid generation is dominant in most land plants.
True
In gymnosperms, how is a seed formed?
Once the sperm cell generated by the pollen grain reaches the egg, a zygote and then a seed will form.
Fifteen years ago, researchers thought that a platyhelminthe was the ancestor to all protostomes. Is this true?
No. It was believed because platyherlminthe have no coelom, but the ancestor to all protostomes was complex, and that its gradual development into a more simple structure like a pseudocoelom in nematodes or no coelom in platyhelminthes is a sign of evolution.
Associate a characteristic with a species: Sponges, Nematodes and Jellyfish.
- Embryo does not have endoderm nor ectoderm
- Radial symmetry
- Fixed number of cells when reaching maturity
Sponges → Embryo does not have endoderm nor ectoderm
Nematodes → Fixed number of cells when reaching maturity
Jellyfish → Radial symmetry
What is the ploidy level of the endosperm in angiosperms?
3n.
In humans, peristalsis is the set of muscular contractions allowing the progression of food inside the digestive tract following the contraction of muscles (derivatives of mesoderm) surrounding the digestive tract (derived from endoderm). Would nematodes be capable of peristalsis?
Nematodes have a pseudocoelom hence, no mesoderm around the digestive tract. Therefore, since there is no mesoderm around the intestines, it is impossible for them to develop the muscles that would allow peristalsis to occur.
What portion of the vascular plants’ life cycle (sporophyte, gametophyte, spore, gamete) would survive in a thinner atmosphere?
The sporophyte (diploid) would be an advantage in a thinner atmosphere because diploid dominance provides a “backup” copy of DNA so that if the first copy was to be damaged by mutation or changes in the environment (thinner atmosphere), the organisms would still survive.
What structure could help a deciduous tree survive during a rough winter?
An amyoplast.
What cell junction between the cells lining an artery could allow a macrophage (a type of white blood cells) to migrate out of a blood vessel?
Anchoring junctions.
Why are carbohydrates found outside the membrane and not inside like cholesterol is?
Because carbohydrates are polar/hydrophilic and therefore would not be soluble in the cell membrane.
Which cell structure contains its own genome between these:
a. Mitochondria
b. The central vacuole
c. Lysosomes
d. The smooth endoplasmic reticulum
e. Transport vesicles
Mitochondria.
Aside from the nucleus, the only organelles that contain their own DNA are plastids. Here, only amyloplasts are plastids.
What directly allows the formation of hyperosmotic urine in the nephrons of mammals?
The passive transport of water from the collecting duct into the interstitial fluids of the renal medulla
In two neurons, the synapse process doesn’t work anymore because the postsynaptic neuron always fails to generate a nerve impulse following the exocytosis of neurotransmitters from the presynaptic neuron into the synaptic cleft.
What could explain this?
A mutated neurotransmitter receptor on the postsynaptic neuron’s dendrite.
How do you convert a phospholipid into a triglyceride?
Replace the hydrophilic head by a fatty acid chain
A red blood cell is swollen and about to burst.
- Describe the conditions inside the cell in relation to the extracellular fluids?
- Describe the conditions outside the cell in relation to the inside of the cell?
- Hypertonic
- Hypotonic
The inside had more solute than outside, so the solvent from outside diffused into the cell.
Why is it useful to use a phosphorylation cascade in signaling pathways rather than just 1 messenger protein, which would be much simpler?
Because a phosphorylation cascade allows the amplification of the signal.
Harmful proteins that are produced in the rough endoplasmic reticulum are secreted outside the cell instead of being placed inside lysosomes. Where would you find the cause?
The Golgi apparatus: responsible for the sorting and secretion of proteins.
In which cell organelle would the assembling into new copies and packaging inside a lipid vesicle of viral proteins occur?
In the Golgi apparatus.
Which category of energy system would a snake (or any living being) represent?
Open system.
Find the most adapted transport type for Leucine along its concentration gradient.
Facilitated diffusion
Find the most adapted transport type for Ca2+ along its concentration gradient
Gated channel
Find the most adapted transport type for Water through a semi-permeable membrane
Osmosis
Find the most adapted transport type for Glucose against its concentration gradient.
Symport
Find the most adapted transport type for Glycogen
Bulk-phase endocytosis
Find the most adapted transport type for K+ against its concentration gradient.
Pump
What is the function of the Na+/K+ pump for the nerve impulse?
Building the resting membrane potential.
What is the function of the Na+ leak channel for the nerve impulse?
Maintaining the resting membrane potential.
What is the function of the Na+ gated channel for the nerve impulse?
Depolarizing the membrane.
Describe the path of the synthesis of the hormone insulin.
First, a mRNA will be synthesized and will exit the nucleus via [a nuclear pore]. Since insulin needs to go out of the cell, the mRNA will be translated by a [membrane bound ribosome] directly into the [Rough endoplasmic reticulum] where the polypeptide would be folded into a protein. From there, a(n) [Transport vesicle] will bud and a motor protein will carry it by walking on a [Microtubule] until it merges with the [Golgi apparatus]. Then, a [Secretory vesicle] containing insulin will form and will travel and merge with the [Cell membrane] where insulin will be expelled out of the cell in the process.
Are beta sheet and random coils more or less hydrophobic than alpha helices?
Less hydrophobic because they are more or less polar, whereas the alpha helices are non polar, hence hydrophobic.
What type of tertiary structure could be found between beta sheets and random coils?
Ionic bonds and H-bonding could be found between them because they are more or less polar and have some polar and some charged parts. There could be little hydrophobic interactions with the nonpolar parts.
What element is missing for the transport of water through aquaporins from the collecting ducts to the renal medulla to really be considered as secondary active transport?
In secondary active transport, there is always a driving ion that is cotransported with the molecule of interest. Here, there is no driving ion, so we cannot consider this as secondary active transport.
Which is reduced:
NADH or NAD+?
Glucose or G3P?
NADH, Glucose.
A mutation in which process could explain how the ancestral anaerobic respiration became aerobic respiration?
A mutation in a gene coding for one of the proteins found in complex 4 of the ETC. Explanation: since the only difference between aerobic respiration and anaerobic respiration is the final electron acceptor, the only mutation that could change the electron acceptor that is used is a mutation in complex 4, since only complex 4 that interacts with it.
When adenosine monophosphate (AMP) binds to glycogen phosphorylase, it changes the conformation of the enzyme to make the active site available and therefore able to bind glycogen.
AMP is the ________________ of glycogen phosphorylase.
Allosteric activator.
Why don’t we find “energy depletion” among the most common bad effects of the keto diet?
Because fats contain glycerol and fatty acids, which will enter cellular respiration to generate energy even in the absence of glucose.
In terms of free energy, would you expect the following reaction to be endergonic or exergonic?
NAD+ –> NADH.
- gain in potential energy (+delta H) because there is an additional bond
- entropy decreases (-delta S) because the atoms are less dispersed
= +delta H and a -delta S can only give a +delta G = endergonic (nonspontaneous).
Would the concentration gradient in the thylakoid lumen be stronger, weaker, or the same if only cyclic photophosphorylation was used instead of a combination of both light-dependent reactions?
WEAKER since in cyclic photophosphorylation, you don’t have
- the splitting of water realeasing H+ in the thylakoid lumen
- the reduction of NADP+ to NADPH removing a proton from the stroma.
which contribute to building the proton gradient.
Where would you find the highest concentration of H+ in a plant cell?
Thylakoid lumen (proton concentration gradient is generated across the thylakoid membrane)
Where would you find the highest concentration of G3P in a plant cell?
Stroma (where the Calvin cycle occurs)
Where would you fins the highest concentration of CO2 in a plant cell?
Cytoplasm (rubisco decreases the CO2 concentration in the stroma)
Can another process lead to the synthesis of glucose following the release of G3P molecules from the stroma to the cytoplasm of plant cells?
Yes: Gluconeogenesis.
In terms of carbon atoms, how can the Calvin cycle afford to lose 1 G3P molecule for every 6 G3P molecules synthesized?
By converting 3 RuBP molecules into six 3-phosphoglycerate molecules. (by gaining more carbon!)
What is the final electron acceptor in cyclic photophosphorylation?
None.
True or false: Fermentation further oxidizes the products of glycolysis to yield 2 additional ATPs.
False
True or false: In plants, cellular respiration only occurs in the roots, not in the photosynthetic areas of the plants.
Fasle
True or false: In plants, cellular respiration is done during the day and also at night.
True
What would be the main product(s) of the dark reactions of photosynthesis?
Carbohydrates.
What part of photophosphorylation is not completely essential for photosynthesis to work?
Ferredoxin giving electrons back to the plastoquinone pool. (not essential for non cyclic photophosphorylation)
What is the main function of pyruvate oxidation?
The reduction of electron carrier molecules via the oxidation of pyruvate to an acetyl group.
If you are very hungry and low on energy, what is the most common allosteric conformation of the phosphofructokinase (PFK) enzymes found in your cells
ADP bound to PFK, PFK active.
What location(s) in the cell has the lowest pH (most acidic)?
- The intermembrane space of mitochondria
- The thylakoid lumen
Where can you find the archenteron in a fully developed human?
It would be the cavity inside the digestive tract
Why do CAM plants perform the C4 pathway only at night?
To prevent water loss during the day. For the C4 pathway, the stomata open = water loss
What should be used to convert stem cells into fully developed differentiated cells?
Use the right transcription factors in a correct order to trigger the differentiation of the cells.
How many ATP molecules from SUBSTRATE LEVEL PHOSPHORYLATION will be produced by the breakdown of 1 pyruvate molecule entering cellular respiration in the cytoplasm?
1 in the citric acid cycle.
Give 2 examples to show that cellular respiration is said to be a very flexible metabolic pathway.
- alanine is converted into pyruvate to enter pyruvate oxidation
- leucine is converted into acetyl units to enter the citric acid cycle
The advantage of cellular respiration being flexible is that it does not need to rely only on glucose to work. If glucose is absent, it still has access to plenty of other substrates to keep producing energy.
