bio 1500 final
The myosin gene family consists of 18 different genes that code for different versions of myosin protein, which is involved in movement. Some versions of this protein are used in muscle contraction, others are used for transporting vesicles around cells or moving chloroplasts in response to light. Which of the following statements about the myosin genes is mostly likely true?
The 18 different genes arose as a result of gene duplication events.
What does it mean to say that a fetus experiences high-altitude conditions?
The PO2 of the mother's blood is similar to the PO2 of the atmosphere at high altitudes.
As Hb moves from the environment of the lungs to the environment of active tissues in the body, the Hb molecule changes shape. What is the outcome of this change?
The affinity of Hb for O2 decreases
Muscle cells are specialized for contracting. Cells in the pancreas are specialized for producing insulin. What enables cells to specialize in a particular function?
The expression of genes varies among cells.
What is the "vital capacity" of the human lung?
The maximum amount of air one can expel from the lungs after a maximum inhalation
Sperm cells rely on the propeller-like motion of the flagellum (= 'tail') to swim. This motion requires the use of ATP. What happens to ATP when it is 'used' to generate the motion?
The molecule loses a phosphate group. ADP (Adenosine DI-phosphate) is the lower energy form of the molecule, and ATP (Adenosine TRI-phosphate) is the higher energy form. When a chemical reaction requires energy, the third phosphate group can be removed from an ADP molecule and the energy that was in the bond can be used for other things, such as contracting muscle.
In preparation for birth, a human fetus switches from producing fetal hemoglobin to producing adult hemoglobin. What would be a disadvantage of having only fetal hemoglobin once you are no longer inside your mother's womb?
The newborn's hemoglobin wouldn't release enough O2 to the active tissues.
The three vaccines currently ready for approval have the following characteristic in common:
The only component that is similar to a part of the Corona-Virus is the mRNA of the spike protein
What is an important consequence of the residual volume of the lung?
The partial pressure of O2 is lower inside of the lung than outside.
A proton gradient has just been generated across a mitochondrial membrane. What will happen next?
The protons will flow across the membrane through ATP synthase.
Evaluate this statement: 'If evidence supports a hypothesis, it is upgraded to a theory. If the theory gains even more evidence, it may be upgraded to a law.'
The statement is false because hypotheses, theories, and laws are all different things.
Why did O2 concentrations in the atmosphere increase so dramatically during the Carboniferous?
There was an increase in the rate of photosynthesis relative to the rate of cellular respiration.
What do photosynthesis and cellular respiration have in common?
They both make use of each other's by-products.
Most animals that are larger than a single cell have a body part that is adapted to serve as a specialized respiratory surface. Which of the following is a characteristic of ALL animal respiratory surfaces?
They have a large surface area. The larger the surface area, the more efficient diffusion is. Not all animals fall into the other categories: mammals have their respiratory surface on the inside, but flatworms have it on the outside; the insect respiratory system is not connected to a its circulatory system -the oxygen moves directly from the trachea (tubes) into each cell. Not all animals have tubes that carry air: fish, for example, and worms, lack tubes.
Puncture wounds, such as those obtained by stepping on nails, are particularly susceptible to infections by the bacteria that cause tetanus. These bacteria can only survive in environments in which there is very little oxygen present, such as inside deep wounds. Based on this information, what can you conclude about these bacteria?
They perform glycolysis, but not the additional steps of cellular respiration.
What was the importance of Cyanobacteria for the evolution of life?
They produced O2 as a by-product and transformed earth geology. Cyanobacteria were early photosynthetic organisms. They released O2 as a by-product of photosynthesis.
You learned about five different types of vaccines that provide immunity against a variety of pathogens. What do they all have in common?
They stimulate a response from the specific immune system.
According to members of medical school selection committees, what is a good way to prepare for medical school?
To develop team working skills and to practice being an active learner. Surveys of medical school admissions offices ranked team-working skills and taking control of one's learning much higher than biological content knowledge.
Why do cells perform photosynthesis?
To make glucose The product of photosynthesis used by the plant is glucose
In the experiment by Klok and colleagues, the offspring of the 7th generation in 40% O2atmosphere were transferred back into an atmosphere of 21% O2before the body mass was measured. What was the purpose of this step?
To test whether the changes in body size were genetically determined the purpose of the experiment was to determine whether there was an evolutionary response to the higher oxygen levels. Evolution requires a genetic change in the population. It's possible that the larger size in the high-O2 conditions was not the resultof a genetic change in the population, but rather that more O2 enables you grow larger in the same way that eating more food enables you to grow larger. Moving the animals back to 21% O2 and seeing whether they still grew larger was a test of whether the large size in the high O2 conditions was the result of a genetic change or not.
Explain your observations of reddish light coming from Chlorophyll when lit with bright white light. Include a description of fluorescence in your explanation.
When a molecule is struck by a photon, the energy is absorbed and excited electrons into a higher energy state. The electron quickly drops to it ground state since it has nowhere to go, releasing the energy as light (often at a longer wavelength hence the red color) This is the idea of fluorescence which is when a substance absorbs light energy and then re-emits it at a different wavelength.
Imagine a new coronavirus has jumped to humans and you want to know how likely this virus is to spread widely in human populations. Which of the following is the most appropriate question to ask?
Which part of the respiratory system does it infect?
You have a culture of cells growing in a flask in the laboratory. You observe that they produce carbon dioxide as a result of cellular respiration. Could the cells in the flask be plant cells?
Yes, because plant cells use cellular respiration to generate ATP.
Evolution.
a change in allele frequencies in a population ○ Natural selection is one of these processes ○ Does not necessarily mean that a new trait appears
One area in a cell has a higher density of a certain type of molecule compared to a neighboring area. This situation describes:
a concentration gradient
A particular segment of a DNA molecule unwinds temporarily and one side of it is used as a template to make a molecule of mRNA. This particular segment of DNA is:
a gene
How long did Dinosaurs roam on Earth
about 165 million years According to your lecture on the history of life, dinosaurs evolved about 230 million years ago and went extinct 65 million years ago. 230-65=165 million years.
•explain the function of the air sacs and how the airflow in birds directs oxygen-rich air through the lungs at all stages of respiration
airflow into the parabronchi (gas exchange site) flows in only ONE direction, so O2 and CO2 never mix
A population of geese is migrating at higher and higher altitudes as a mountain range slowly grows along their migration route. Before, during, and after the growth of the mountains, mutations in the hemoglobin gene arise in this population. Which amino acids are most likely to be affected by these constantly occurring mutations?
all amino acids are equally liekly
A plant cell uses photosynthesis to make a molecule of glucose. What will the plant use that glucose for?
as an input to cellular respiration to make lipids to make other carbohydrates to make proteins
•Recognize that mutations can be neutral, harmful, or beneficial.
bad: loss of functiongood: gain function neutral: end up w no change or a change that doesnt affect anything (point mutation most likely), ex. changing base still codes for same amino acid or dif amino acid but still polar might not change silent
•Explain how a fetus obtains oxygen.
bc has to get out of pool of mixed blood in placenta and move thru placenta, has to have high affinity (alt) HB or less 23hbg levels.. .-post fert. (2 weeks), diffusion o2 only -embryonic HB, highest HB, o2 pick up in yolk sac -fetal HB, has dif high hb bc the 23 BPG doesnt bind = right shift (10 weeks to 6 months in world)
Philip is the star of his college track team. When Phil is running in a long race, his muscle cells start out performing cellular respiration, but toward the end of the race many of the cells switch to lactic acid fermentation. Why do Phil's muscle cells make this switch?
because the oxygen used by the muscles cannot be replaced fast enough to sustain respiration
Determine the correct sequence of the following steps in replication by a DNA virus:
bind to receptor release genome into host cell copy viral DNA into RNA manufacture viral proteins assemble proteins into virions virions exit cell
•explain why the high efficiency respiratory system of birds does not work sufficiently well at high altitude.
bird efficient: unidir., little dead volume, slow breathing rate, small diffusion, larger lung surface -bar-headed gas have alanine not proline = gap = more affective -high doesnt work bc is p02= po2 of atmosphere and po2 decreases at higher alts
You are touring an abandoned gold mine deep under the ground. The passageways are illuminated by the occasional lamp attached to the wall. You are surprised to see that small plants are growing near the lamps, even though you are deep in the ground. You realize that these plants are able to grow here because the lamps are emitting:
blue light of the light colors listed here, Chlorophyll absorbs only blue light, while the others are reflected.
In the late fall, it's common for local songbirds to consume berries containing alcohol. The birds become intoxicated and are prone to flying into windows. The alcohol in the berries is produced by micro-organisms that break down sugar in the berries. Given this information, what else is being produced in the fermenting berries?
carbon dioxide
When a plant cell produces glucose, the carbon atoms in the glucose molecule have come from
carbon dioxide, CO2, water, chlorophyll, ATP
Which three of the following are types of transport proteins?
channel proteins aquaporins carrier proteins
Describe evidence that increased atmospheric temperatures are the result of an increase in greenhouse gas composition rather than changes in the sun.
climate change imp. WVs: visible and infrared -CO2, CH4, N2O, H2O -visible spectrum rays pass through GH gases, part of this is absorbed by plants for photosynthesis -other part of energy is absorbed and is converted to longer energy like infrared heat energy -infrared energy doesnt pass as easy thru GH gases, some goes in to space, some absorbed by GH and reradiated out in all directions, warming earth
Which of the following situations typically selects for larger body size in mammals?
competition among males for mates
Explain why a change in an aa-sequencemay change the 3D structure of a protein
could polar/nonpolar, nonpolar curves inside away from water
•Know examples of things or situations that cause genes to be turned on or off.
developmental stage type of tissure stage of physiological cycle like menstration external env cues like food sunlight temp.
Explain how we know that the Hb adaptations of birds living at high altitudes in different parts of the world is an example of convergent evolution.
dif locations!! same adaptations but didnt breed together and mutations are same, but dif. genetics
Which of the following must occur for two populations of the same species of monkey to evolve into two different species of monkey?
diff alleles must spread through pop
Recall 2 more examples how gradients in cells are used to do work.
diffusion, atp synthase
Recall the general function that gradients have in cells.
energy storage
Describe an effective experimental design to determine whether an environmental variable imposes selection on a trait
experiment w quick life cycle insects at different levels of o2 w control group.. have multiple generations for evolution
Describe the hypothesized reasons for the decline in O2during the late Permian
fall during carb: turned to permian which had a 1. drier climate, 2. sandy sediments which allowed decomp. and 3. evolved fungi that can break down carbon (less buried) = o2 drop
Memorize the outputs of fermentation
fermentation: when no O2 is available, instead of normal CR, pyruvate (product of glycolysis) undergoes fermentation (instead of citric acid cycle) and is converted to -alcohol and co2 OR -lactic acid (yogurt, cheese) *NO ATPS MADE, except 2 in glycolysis Outputs of fermentation Alcohol & CO2Lactate --Lactic acid
Which of the following is an important source of water in the Paramos ecosystem of the Andes?
fog
.Know the definitions of: gas exchange, tidal volume, vital capacity, alveoli, ventilation
gas exchange movement of O2 from air into blood; and CO2 from blood into air alveoli parts of the lungs in which gases are exchanged
Viruses lack all of the following except:
genes
•Define 'regulatory genes,' explain how they work, and why they are important.
genes coding for transcription factors (what regulate the attachment of rna polymerase which starts transcription, protein synthesis, like activator/repressor proteins) -ex. can code for repressor protein -controls expression of other genes by turning them on/off bc if makes repressor, can bind to promoter and inhibit being made = off = not expressed
population,
group of organisms that breed with each other
Define a species according to the Biological Species Concept.•
group of organisms with the potential to breed with each other and produce live, fertile offspring-probs = asexual reproduction or sterile animals (mule) (both wouldnt be considered species then)
Explain what a gene or protein family is, using the globin genes/proteins as an example.
group of structurally and functionally related genes/proteins as a result of shared evolutionary history... ex. hb subunits, 7, all have similar structure and function, 4 on the same chromosome, these 4 have the same # of AA (length)
Given what you learned about the ACE2 receptor, what might be a side effect of administering a drug that blocks this receptor in Covid-19 patients?
high BP
Recognize what it means if a gene is expressed vs not expressed, turned on vs turned off, or up-regulated vs down-regulated.
high alt hb is less efficient at low altitudes, not ideal but works...2 genes for hb turned on and then expressed? -all cells in the body have 46 chromosomes and all genes, NOT all are active everywhere..expressed: "made" transcribed and translatedgene expression is regulated by turning genes on/off (on = being made, off = no transcription, not made) -if a gene is off, it wont be transcribed (aka expressed) -if a gene is on, it will be expressed gene expression regulated by 1. turning genes on/off and 2. varying the rate of production (up/down regulated)(activator/repressor proteins), making more/less of protein)(ex. menstrual cycle = more hormones)
.summarize how pH, PCO2, temperature, and 2,3-BPG change the tertiary and quaternary structure of Hb and thus its O2affinity.
higher pco2, 2,3-bpg, temp and LOWER ph - right shift (lower affinity) -CO2, H+, and 2-3 BPG are charged or polar -attached to charged amino acids on outside of subunits -changes tertiary and quaternary structure of Hb -->CHANGES FUNCTION -change of a single amino acid could change function **changes in the environment of Hb reversibly alter its structure in ways that change its affinity for O2
.explain why human Hb does not work sufficiently at high altitude, by relating PO2at low and high altitude to the O2Hb dissociation curve.
human Hb does not work at high altitudes because it does not have the ability to bind O2 in the lungs because there is low O2 amounts in the atmosphere. Above 6000m, pO2 is too low to effectively load HB with O2 to allow sustained work.
.Recognize differences between human and insect respiratory systems
humans: lungs, transport of O2: blood proteins (hemoglobin) insects: tracheal tubes & air sacs, transport of O2: tracheal tubes, diffusion
How does facilitated transport differ from diffusion?
in facilitated transport, the substance passes through a pore, or tunnel, inside other molecules in the membrane
How does facilitated transport differ from diffusion?
in facilitated transport, the substance passes through a pore, or tunnel, inside other molecules in the membrane, in facilitated transport, the substance passes through a pore, or tunnel, inside other molecules in the membrane Facilitated transport involves proteins that make it easier for certain molecules to pass through membranes, rather than through simple diffusion.
-Memorize the inputs and outputs of cellular respiration
in mitochondriain: glucose, o2 out: ATP, co2, h2o
Know the functions of the mammalian respiratory system
inhale thru mouth, air in lungs -lungs, o2 diffuses to red blood cells -o2 binds to blood pigments (hemoglobin) in RBC -in body, o2 released from hemoglobin, diffuses to cells -o2 used in CR, co2 byproduct goes to blood -co2 dissolves in blood
Compare visible light energy with the rest of the electromagnetic spectrum: how is it similar, what makes it special to us?
it is special because its the only light we can see with our eyes,
Categorize different energy forms as 'kinetic' or 'potential'
kinetic energy is motion and heat, light, and movement/// potential. energy is chemical energy 1. Kinetic energy: energy of movement-heat: movement of particles-light: movement of photons-electricity: movement of electrons 2. Potential energy: stored energy-chemical: energy stored within chemical bonds
The highest rates of diffusion are associated with
large diffusion surface area steep concentration gradient high temperatures
Compared with at sea level, the partial pressure of O2 on Mt. Everest is ...
lower, because there are fewer air molecules in total at high altitudes.
Explain how the acquired immune response leads to long term immunity
memory cells
Describe the oxygen environment of the womb.
moms body rejects baby bc not same exact genes... -baby w umbilical cord with red lining part called placenta, o2 comes thru placenta and umbilical cord -low o2 availability bc mom and babys blood vessels go in to a 'pool' of moms blood, has o2 but also other like co2 bc mixed, so low po2.. gas exchange
•Explain the steps involved in the evolution of the high-altitude Hb, using the terms selection, mutation, protein structure, affinity, variation, alleles, phenotype, heritable.
nat sel. postulates (indvs vary in traits, some variation is heritable, more offspring if produced than survive to reproduce, survival and reprod are non randmon, more favorable traits pass most on) random mutations occured and beneficial ones that changed the dna bases (forming new alleles) to something good like alanine which changed the phenotype of protein structure stayed and evolved in to more of the population over time. this new hb had a higher affinity for o2 selection favored high alt hb *ancestors of geese had normal affinity hb... mutations that changed quaternary of hb and affinity were disregarded... as mts rose, geese had to fly higher, any goose w high affinity hb was favored... since hb structure is heritable, geese passed onto offspring and survived better and the new allele became more common till all geese had
•Know the common sources of new genes, including mechanisms of gene duplication.
organisms have dif # of genes, this dif number comes from pseudogenes(no longer active bc of too many mutations) or from NEW genes -mutations that make new start codons-viral genes (virus) -duplications, extra copy of gene can then mutate and acquire new function--- causes: unequal crossing during meiosis (when 1 chromosome from mom and dad cross to make 2 chromosomes, 1 is inverse of other... if they are not equal inverses = unequal, extra of some/less of others) ---causes: mistakes during DNA rep. (copying) ---causes:dupl. of entire chromosome
Types: Differentiate among point mutations, frame-shift mutations, and chromosomal mutations
point: 1 base changes to another, only slightly likely to have an affect insertion/deletion (frame shift): 1 or more bases are inserted/removed from a gene, causes a shift in the frame for all codons downstream, likely to be dysfunctional duplication: large chunk of DNA is duplicated in strand (MANY bases), may/can have big impact chromosomal: large scale change in number of chromosomes, largest change
Describe the steps involved in the most common form of speciation
process evolving into 2 species -geographically isolated, mate wn own population -genetic difs build up, can be due to selection pressure like hb needs, high or low o2 -if difs are great enough that they cannot produce viable offspring, populations are now separate species
Define convergent evolution
process in which unrelated species from similar environments have adaptations that seem very similar
When a cell needs to stop the production of a particular protein, a(n) repressor protein binds to the ????? of the gene, initiating transcription by ????????
promtoer region RNA polymerase
Identify the wavelengths (i.e. colors) of light absorbed by chlorophyll
red, blue, and violet
Describe the potential outcomes of light striking an object
reflected, transmitted, absorbed
•Connect variation in gene expression with differentiation/specialization of cells.
regulatory genes cause tissue differentiation during development, done by transcription factors, turning on specific things needed -ex. SRY gene on Y chromosome, sry codes for activator protein (recruits rna polymerase) that turns on other genes needed to develop testes
Explain the two reasons for an imbalance in this cycle that led to the increased O2 during the Carboniferous.
rise during carb: land dominated by swamps, vegetation, trees (LOTS of PS) BUT lots of carbon buried (in swamps)(early trees also used lignin not cellulose as structural molecule & no decomposers could break down) instead of CR... buried c = fossil fuels... more o2 bc C not used in O2 CR... ->photosyn = organic carbons and o2... organic carbons buried to make coal and for lignin which made bigger plants and more o2 (but no more CR)
Amylase is an enzyme that breaks down starch. Suppose you put corn starch in a test tube with amylase. When you examine the contents of the test tube later, what will you find?
simple sugars
What does it mean if a channel is gated? (Compare this question - and your answer - with the previous question!)
sometimes the channel allows molecules to pass through, and sometimes it doesn't
Explain how gradients are used in cells using the example of ATP Synthase
stores H+ and pushed inward which provides energy for ATP synthase
Which one of the following variables influences the affinity of Hb for O2 in different parts of the body?
temp of blood
Drs. Bush and Schul will be eating red pepper slices today with their lunch today. The peppers grew on a farm. Where did the pepper plant get most of the matter that makes up the pepper?
the air
What does it mean if a channel is selective?
the channel allows only certain substances to pass through, but not others
fitness
the genetic contribution of an individual to the next generation's gene pool relative to the average for the population, usually measured by the number of offspring or close kin that survive to reproductive age.
Which of the following topics from our course would be best classified at the cellular level?
the production of carbohydrates through photosynthesis
What is diffusion?
the spontaneous movement of molecules away from areas of highest density
What is the difference (or relationship) between the terms diffusion and osmosis?
they both function in the same way, but osmosis refers specifically to the diffusion of water molecules
After molecules have moved around until there is no longer a concentration gradient, how do the molecules behave?
they continue moving, but their density remains relatively even throughout the space
Based on our lecture, what characteristic of bats has been argued to account (indirectly) for the fact that they are reservoirs of viruses?
they fly
What is the function of transcription during protein synthesis?
to copy info in a gene
What is the function of the electron transport chain in cellular respiration?
to generate a proton gradient across the membrane
What is the function of cellular respiration?
to make ATP
•Draw and interpret Hb-O2 dissociation curves for fetal hemoglobin.
to the left of normal adult bc has a higher o2 affinity which helps the fetus extract more hb from the mothers blood bc it 1. doesnt breathe thru lungs (these have amniotic fluid) and 2. exchanges blood 'pool' w mom which has a low po2 bc its blood w o2 and co2
adaptation
trait that increase fitness of individual with this trait relative to others without it ○ Trait produced by the process of natural selection
•Describe the roles of transcription factors, activator proteins, repressor proteins, promoters, and RNA polymerase in gene expression.
transcription begins when the enzyme RNA polymerase binds to a sequence of dna called a promoter, just upstream from a gene -all dna, part of dna sequences for promoter which signals enzyme rna polymerase binding-transcription factors regulate attachment of rna polymerase (which starts transcription = making protein), 2 types.. ----activator proteins, recruit rna polymerase to promoter, start transcription (up-reg) ----repressor proteins, block rna poly and prevent transcription (down-reg)
Recognize the inter-relationship between the two processes
use each other's byproducts to function
the energy in the bonds of the glucose molecule has come from
water, sunlight, oxygen, ATP, sunlight
. The daughter of your instructor has a lot of "pride" (=rainbow) things in her room. Among others, she has a rainbow light chain, with the different bulbs producing violet, blue, green, yellow, orange, and red light. How does the electromagnetic radiation from the different light bulbs differ?They differ in their:
wavelengths All of the forms of energy on the electromagnetic spectrum are physically the same thing -they're just different wavelengths. The different wavelengths of light stimulate different receptors in our eyes, causing us to perceive the different colors.
Identify the function of cellular respiration
*cellular respiration: function is to produce ATP,
Describe the insect respiratory system
*insect - no blood to transport O2, have tracheae bring o2 directly to cells, spiracles are openings to outside of body where co2 leaves/o2 enters... travels mostly by diffusion (large insects have air pumped in/our of air sacks and a large trachea to help) diffusion in small trachea *human*similarities*differences -Insects have no blood that transports O2-Instead: trachea brings O2 directly to cells--spiracles: openings to outside-O2 and CO2 travel largely through diffusion--becomes a problem at long distances-Large and active insects: pump air in/out of air sacs and large trachea-small insects: diffusion through trachea-respiratory system limits insects' size
identify common features between the two processes
*plants do both *we do just glycolysis + CR -source of electrons (PS: water, CR: NADPH, FADH2) -final acceptor of electrons (PS: NAD+, CR: O2) -function (PS: glucose, CR: ATP) -same: etc, atp synthase, nadph (electron carrier), use byproducts -electron transport chain -ATP synthase-Proton gradient -NADPH (electron carrier) -make use of each other's byproducts -cyclic component (PS: Calvin cycle; CR: citric acid cycle)
Recall the two general parts of the vertebrate immune system and their basic components
- Innate immune system : preconfigured responses to set of stimuli (all organisms) - Acquired immune system: IS 'learns' to recognize pathogen (only in vertebrates - animals w spine) innate - Complex processes providing an immediate response to detect pathogens Immune sensing - Detects molecules typical of pathogens or damaged cells - Marking them with special molecules (cytokines) Innate immune cells ; leukocytes (WBC), macrophages - Identify and kill pathogens through phagocytes - Defend against multi-cellular parasites by secreting chemicals - Natural killer cells- attack virus- infected or tumor cells Inflammation -Increased blood flow, swelling, redness, heat, fever - Release of interleukins, interferons (anti-viral) - Recruits immune cells to site of infection Activation of 'Acquired immune system'
Describe how the structure of our respiratory system facilitates gas exchange
-Alveoli: close contact of air and blood -separated by thickness of 2 cells -Diffusion moves O2 and CO2 from high to low concentration -O2 binds to hemoglobin in RBC --removes it from solution, keeps O2 concentration low ---and diffusion going fast
.Recall the reason for 'death-zone' and where a death zone occurs
-There is insufficient oxygen that prevents people from remaining there for more than 48 hours-it like being slowly choked-treacherous terrain, high winds and low temps-frost bite, blood vessels in the skin contract to preserve core body temps-body will use up its store of oxygen faster than breathing can replenish it
List the steps in mammalian respiration
-blood transports co2 to lungs to be breathed out (exhaled)-------------------------------------------------------------------------------------- residual lung volume: 'used' air left in lung = po2 lower in lungs than atmosphere-------------------------breathing occurs in bulk flow, movement of all solutes together = high to low pressure?
Explain how the circular processes of photosynthesis and cellular respiration result in the cycling of carbon within ecosystems.
-carbon backbone-some carbon produced thru PS is used to build other molecules in the cell (not broken down in CR), including cellulose in plants-carbon that makes up plants comes from air(CO2)-carbon is put back in the atmosphere by decomposers breaking down dead matter (same as CR)*increase in PS relative to CR = more o2
•Relate developmental changes in Hb to gene duplication and to changes in gene expression.
-dif hb could be bc of dif tissue types which causes dif genes turned on/off OR -gene duplication couldve made mutations for this HB, arising throughout history, varying in o2 affinity and these are then expressed at dif. life stages ***high alt in humans? - doesnt work, at high alts, we get dif regulations of affinity like less 2,3 BPG (right shift) and more red blood cells and Hb
explain how the bird respiratory system differs from that of mammals
-flying requires much more o2 than running -lung with anterior and posterior air sacs -inhale thru posterior sacs through parabronchi (gas exchange that stores fresh/used air) into anterior air sac -exhale from anterior sac, from post. air sac thru parabronchi -parabronchi flow is unidirectional, it always has fresh air in it (ours is bidrect.) -sacs dont contract like lungs -birds: po2 of atmosphere = more o2 available
memorize the function of myoglobin in the body •explain how the structure and the O2binding properties of myoglobin relate to each other.
-meat is bright red because has myoglobin has oxygen (leave unsealed so o2 enters) -dark red has no oxygen -brown has water, not o2-bright pink when CO or NO (sealed) -muscles have protein myoglobin that stores o2, 1 globin + 1 heme... stores for when there is high energy demand (exercising) -myoglobin curve is to the left and straight up bc only 1 group (hemo has 4, each has higher affinity for o2)
Identify at which level a particular biological process occurs -Provide examples of how each level of biological organization is reflected in our explanation for the large size of dragonflies during the Carboniferous
-molecular (structure or behavior or molecules)(organic molecules, ATP synthase, ETC) -cellular (processes performed by cells)(PS, CR, fermentation, role of gradients) -organismal (physiology, how do they work)(more o2 = more diffusion = more resp = bigger, body size, reproduction) -ecological (interactions bt species or bt an organism and the environment) (lack of predation, break down of lignin, vegetation, carbon cycle, O2 revolution) -evolutionary (change over time)(NS, allele freq = change in traits, o2 influence on body size)
Describe how the geological history of the Himalayas explains why the bar-headed geese migrate over them.
-now: low in india, high in china mts., low in mongolia -earlier: india used to be island and started moving towards asia, collided w asian plate and mts. being made -geese started this migration bf the plate movement, happened slowly so not noticeable yearly.... random mutations that were beneficial were evolved slowly to adapt
•Explain why the high altitude Hb may be disadvantageous at low altitudes.
-o2 poisoning -can't let go of bar geese pos solutios at low alt: higher 2,3bpg (lowers, right shift - same as higher temp, higher pco2, and lower ph = right shift) 2 genes, turned on/off**geese have alpha and d sub units, alpha at high, d not tested
.Describe the levels of protein structure (primary-tertiary)
-primary: sequence of amino acids -secondary: interactions bt dif seq. of amino acids-tertiary: structure of polypeptide -quaternary: polypeptides together
-Identify differences between the two processes-
-source of electron in electron transport chain (PS: water; CR: NADPH & FADH2)-Final accepter of electron (PS: NAD+; CR: O2)-Function of process (PS: to make glucose; CR: to make ATP)-Reactions run in reverse:PS: CO2 + H2O + energy --> C6H12O6 + O2CR: C6H12O6 + O2 --> CO2 + H2O + energy
-Memorize the main steps of cellular respiration
1. Glycolysis: "sugar breaking"-glucose is broken into pyruvate --> 2ATP & NADH 2. Pyruvate prep/Citric Acid Cycle (Kerb cycle)-pyruvate is broken down--generates NADH & FADH2---> these carry potential energy via electrons-produces CO2 as byproduct 3. Electron Transport Chain-electrons are supplied by NADH & FADH2-series of redox reactions-- a) one molecule loses electron (oxidation)-- b) one molecule gains electron (reduction) -as electron is passed, it moves to a lower energy state; the energy is used to pump H+ (protons) across the membrane, generating a proton gradient that stores energy -H= re-enters the mitochondrial matrix through ATP synthase (enzyme), generating ATP -O2 is the final acceptor of the electrons, producing H2O as a byproduct**process as a whole produces about 34 ATP
Memorize the four postulates of natural selection.
1. Individuals vary their traits 2. Some of the variation is heritable and is passed to offspring 3. More offspring are produced than survive to reproduce 4. Survival and reproduction are non-random; those with favorable traits reproduce most and pass their genes to the next generation
.Recall the general steps of viral reproduction
1. attachemt to surface of cell via receptor Viral glycoprotein needs to fit receptor on cell - causes specifity of virus for host species and cell type 2. enter cell or inject viral genome into cell 3. replication and gene expression Viral genes direct cell to produce viral proteins DNA- viral genes copied into rna then translated into protein RNA- translated into proteins, (pos). or transcribed from RNA to mRNA Viral RNA can be reverse transcribed into DNA which enters host's genome 4. viral proteins assembled into new virions 5. new virions leave cell -release -cell lyses, releasing virions or - individual virions pass through cell membrane , obtaining lipid envelope - new virions infect other host cells
Describe the role of the proton gradient and ATP synthase
1. glycolysis sugar breaking-glucose broken into pyruvate = 2 atp, nadh 2. pyruvate prep/citric acid cycle-pyruvate broken down = nadh, fadh2 (electron carrier), co2 (as byproduct) 3. Electron transport chain -electrons supplied by nadh and fadn2 -redox reactions (gain/lose) -as passed, moves to a lower e state, the e is used to pump H+ protons across the membrane making a proton gradient that stores e -h+ re-enters the mito. matrix thru ATP synthase(enzyme), making atp -O2 is the final acceptor, h2o = byproduct, atp made proton gradient: powers atp synthase which makes adp+p=atp
.Explain how the O2affinity of Hb decreases in the body, incl. which factors contribute to this decrease and how this facilitates the release of O2in the body.
1. pCO2 increased = right shift = low affinity 2. CO2 dissolved in H2O forms3. H2CO3 --> H+ +HCO 3 --> pH decreases 4. higher temperature (work, cooling in lungs)= right shift of dissociation curve in body=easy to release O2 in body
Identify several different selection pressures that could influence body size and indicate the likely direction of phenotypic change in response to the pressure
1. sexual selection: competition among males favors large size 2. selection for female fecundity (egg/offspring #): favors large size 3. Selection for early reproduction: small size 4. Limited resource availability: small size 5. Predation: large size in predator, small size in prey 6. Locomotion: flight favors small size 7. Temperature: cold favors large size in mammals, small size in ectotherms (e.g. insects)
•Explain the steps of protein synthesis, including the specific roles of DNA, mRNA, codons, start-codons, stop-codons, anticodons, tRNA, the genetic code, and ribosomes.
1.transcription - getting the info from dna in nucleus to the ribosome, where proteins are made (making a copy)... use RNA, single stranded using CGAU (U instead of T)...messenger rna delivers the instructions on the ribosomea.enzyme unzips double stranded DNA of a gene b. one strand of DNA is a template for making mRNA (TGTGCCA = ACACGGU) C. mRNA leaves thru a pore and goes to a ribosome 2. translation - turning the sequence of bases into a sequence of amino acids bound together a.the ribosome binds to the bases 3 at a time (3 bases of mRNA = 1 codon = 1 AA) b. transfer rna (tRNA) brings the correct AAs to the ribosome.. these tRNAs that bring 1 AA & have an anticodon: group of 3 bases on the tRNA (opp of mRNA) c. after trna (anticodon) binds to the codon,the amino acid binds to the previous AA and the trna breaks off and
1.Given what you know about the size of meganeura (the giant dragonflies), what is the minimum number of meganeura wingspans that should be between you and your friend for sufficient social distancing during a Covid-19 pandemic?a.
2 meganeuras Remember that Meganeura had 3-ft wingspans. Giventhat social distancing requirement is 6 ft, you should be 2 Meganeura apart from each other.
According to scientific evidence, approximately how long ago did life first arise on Earth?
3.8 billion years ago
A biologist surveys a population consisting of 400 lizards, of which 100 are gray and 300 are black. The color of a lizard is determined by which allele it has for a particular gene. Two hundred years later, another biologist surveys the same population of lizards. Which of the following counts would indicate that the population has evolved?
300 gray and 600 black
Describe the electron transport chain -how it works and what it accomplishes-
4 complexes, each has a higher affinity for electrons to "pull" it down the chain...electrons from nadh and fadh2 are pulled off and put on complex 1 and pulled down chain, as this is happening, the protons go thru the complexes to the intermembrane space to make the powerful proton gradient (bc of strong repulsive + charges & they hold energy released by electrons as they move DOWN the etc)... o2 accepts electrons at end of ETC and combines w 2h+ to make water as the H+ energy powers ATP synthase (pushing a p on adp) Electron Transport Chain-electrons are supplied by NADH & FADH2-series of redox reactions--a) one molecule loses electron (oxidation)--b) one molecule gains electron (reduction)-as electron is passed, it moves to a lower energy state; the energy is used to pump H+ (protons) across the membrane, generating a proton gradient that stores energy-H= re-enters the mitochondrial matrix through ATP synthase (enzyme), generating ATP-O2 is the final acceptor of the electrons, producing H2O as a byproduct**process as a whole produces about 34 ATP
memorize the basic structure and function of hemoglobin
4 heme groups + 2 alpha, 2 beta
Recall the elevation of Mt. Everest
8,848
Interpret hypothesized evolutionary relationships in a phylogenetic tree based on analysis of common ancestry
A family tree that shows the evolutionary relationships thought to exist among groups of organisms -number of nodes doesnt affect how closely related in common ancestor is same amount -same distance = same evolving time, nodes not always accounted for
Which of the following could be the outcome of hydrolysis?
A protein is broken into individual amino acids. During hydrolysis, a chemical bond is broken between certain atoms in a molecule.
.explain how a left-or right-shift of the binding curve represents a change in affinity
A rightward shift of the curve indicates that hemoglobin has a decreased affinity for oxygen, thus, oxygen actively unloads. A shift to the left indicates increased hemoglobin affinity for oxygen and an increased reluctance to release oxygen.
.Know what an Open Reading Frame is.
A stretch of RNA that is translated all at once. One start codon and one stop codon at the end 2/3 genome of particular virus
What is an adaptation in the context of evolution?
A trait produced by natural selection adaptation is defined as a trait which increases the fitness of individuals that have the trait over individuals without this trait.
.Describe how ACE and ACE2 proteins maintain homeostasis and how it is disrupted by the virus
ACE2- helps manage BP and inflammation ACE- makes ANG II- increases BP and inflammation (good) BUT damages tissues , including alveoli (lungs) and blood vessel linings ACE2 breaks down ANG II - Lowers BP , PROTECTS tissues from damage Together maintain homeostasis , when balanced ACE2 receptors are lost to virus causes - Too much ANG II - More inflammation, cell damage
the main transport form and immediate source of energy in cells
ATP
What makes the death zone deadly for humans?
Air pressure is so low that there is not a sufficient amount of O2 to survive
You have a fish tank filled with water. You put a drop of dye into the water on the left side of the tank. After a while, the dye has spread out a bit, but there is still much more on the left side. If you were to look at a dye molecule on the left side: Which direction is this dye molecule most likely to move in the next moment?
All directions are equally probable. The movement of individual molecules is random.Because there are more molecules in areas of high concentration than low concentration, it is more likely that there will be molecules moving from high to low, than from low to high concentration areas, but each molecule moves randomly of all other molecules, and all directions are therefore equally probable.
Describe the difference between the various alleles of a gene.
Alleles differ in DNA sequence than genes
How does ATP synthase transfer the energy of the proton gradient into ATP?
As the protons pass through the ATP synthase they induce rotation which presses the ADP and Pi close together, so that they form a bond.
You want to determine whether a molecule of Hb is in the tense or relaxed state. All of the following are appropriate questions to ask EXCEPT:
At what altitude is the Hb located?
Compare the atmosphere we breathe (at sea level) and the atmosphere in our lungs, and explain the reason for the difference.
Atmosphere: -pO2: 21 kPa -pCO2: 0.4 kPa Lung: -pO2: 13 kPa -pCO2: 5.0 kPa the difference in the two is because lung atmosphere depends on volume of gas exchanged
Look at the figure below from the Clapham and Karr paper. Which statement provides the evidence that dragonfly size is related to oxygen levels during part of Earth's history?
Between about 300 and 150 million years ago, there is a correlation between oxygen levels and maximum dragonfly size.
Which of the following is a feature of birds that gives them increased respiratory efficiency compared with mammals?
Birds have very little residual volume in their respiratory system, so there isn't mixing of fresh and used air.
The Aardvark and the Ant Eater both have a very long tongue and you hypothesize that this similarity is due to convergent evolution. All of the following observations would support this hypothesis EXCEPT:
Both species evolved from the same recent ancestor that also had a long tongue.
Suppose you develop a drug to remove the methylated cap from viral RNA. How might this be helpful to Covid-19 patients?
By causing the RNA to be destroyed by the cell
According to the paper by Klaphamand Karr, oxygen levels in the atmosphere allowed dragonflies to grow to a large size during the Carboniferous. About 150 million years later, oxygen levels increased once again, but dragonfly size did not.Why not?
By then, predators that could easily capture large dragonflies had evolved, which made it advantageous for dragonflies to be small.
Explain how fermentation differs from cellular respiration and the situations in which it occurs
CR and PS-opposite products -PS beginning: sun, h2o, CO2, atp-PS products: glucose, o2 -CR beginning: glucose -CR products: ATP(energy), co2, h2o Fermentation occurs in cells when there is no O2 available/present.When no O2 is available, the pyruvate undergoes fermentation (instead of the citric acid cycle) and the pyruvate is converted into either1) alcohol and CO2-->bread2)Lactic acid--> cheese, sour cream, yogurtNo ATP is produced through fermentation.BUT... remember that the cell acquired 2 ATPs through glycolysis
Name the four classes of organic molecules & the chemical subunits that each one is made of
Carbohydrates ○ Made of simple sugarsLipids ○ Made of fatty acidsProteins ○ Made of amino acidsNucleic acids ○ Made of nucleotides
Recall the building blocks of the classes of organic molecules
Carbohydrates, lipids, proteins, nucleic acids
Smoked meats often have a pink "smoke ring" on the outside, which becomes wider the longer the meat is exposed to the smoke. What causes this pink coloration of the meat?
Carbon Monoxide binds to the Myoglobin in the meat, which gives the meat a pink color.
.Recall the features by which viruses are categorized
Contain no cellular machinery (ribosomes, mitochondira) Genetic material inside a capsid Virion- viral particle 1Capsid size and shape 1 Helical - infects plants, long and thing 2 Spherical- not perfectly round 2Genetic material - dna vs rna 3Single strand vs double , pos or neg sense Envelope - presence or absence of lipid bilayer on capsid Heterotypic- a pathogen of other animals that is harmless (cowpox virus used as smallpox vaccine) -Inactivated with heat , chemicals, or radiation (pollo, rabies, most flu-vaccines) -Attenuated - active. But less virulent or non-virulent strain (measles, mumps, rubells, plague..) -Toxoid- inactivated toxins - mostly microbial (diptheria , tetanus, rattlesnake for dogs)
Recall the processes that lead to the Great Oxygen Event & how earth looked before and after this event
Cyanobacteria evolved photosynthesis which created O2 as a side effect which lead to Great Oxygen EventBefore: all organisms heterotrophic prokaryotesAfter: Set the stage for geology and biology as we know it today
•Explain how organisms protect themselves from mutations.
DNA repair enzymes fix most mutations, these travel dna strands and find mistakes or false bases and fixes them (ex. two T bases end up next to each other and bind to each other, repair enzymes fix)
Which of the following is a constraint on the ability of living organisms to rely on diffusion to transport molecules?
Diffusion is only efficient over very short distances. Remember the formula we looked at that relates diffusion distance to time: the time is proportional to the square of the distance. Therefore, small increases in diffusion distance require very large increases in time for the diffusion to occur. As a result, diffusion is only an effective form of transport over very small distances.
Describe the chemical and energetic changes that occur as ADP cycles to ATP and back again to ADP
E leaves ATP which makes ADP
Describe two pathways by which SARS-CoV-2 enters cells
Endocytotic pathway - virus taken into endosome= membrane bound vesicle ; virus fuses with endosome membrane, empties genome into host Receptor-mediated fusion- bind to receptor on surface of cell, fuse with cell membrane, empty genes into host cell - Spike protein binds to ACE2 receptors (found on cell in lungs and capillaries) - Spike protein must be modified by TMPRSS2 (enzyme in host membranes ) to fuse with host cell
Apply the first law of. thermodynamics
Energy is never created or. destroyed but it can change. form
Describe the relationships between the terms chromosome, gene, allele, and DNA.
Gene: a segment of DNA with instructions for building a protein □Specifies the sequence of amino acids that make up the proteinAlleles: different possible forms of the same gene □ Differ in DNA sequence and therefore in protein structure they code for □ There may be many different alleles of the same gene □Any one person can max. of two different alleles• Because of two copies of chromosomes
A scientist is interested in the issue of how the bar-headed geese manage to survive while at low altitudes in their wintering grounds in India. She plans her research program to address the following questions. Which one is at the ECOLOGY level?
Given that the geese have less O2 available for flight on their wintering grounds, do they suffer higher risks of predation compared with other species of geese that over-wintering in the same locations?
Which of the following assessment questions would be categorized at the 'Applying' level in Bloom's taxonomy?
Given what you have learned about how the Corona virus gains access to cells, describe a potential treatment that could block the virus from getting in. The 'applying' level of Bloom's Taxonomy refers to situations in which you use the knowledge you gained in new ways.
The sigmoidal (i.e. S) shape of the Hb-O2 dissociation curve indicates that...
Hb picks up O2 much more easily once it is already bound to O2.
Differentiate between a hypothesis and a formal scientific theory
Hypotheses are proposed explanations for a narrow set of phenomena usually based on prior experience, scientific background knowledge, preliminary observations, and logic.Theories are broad explanations for a wide range of phenomena and can often integrate and generalize many hypotheses.
At the end of the light-dependent reactions of photosynthesis, where is the energy from the sun located?
In the chemical bonds of ATP molecules The light dependent reaction builds a proton gradient which then powers the ATP synthase, which puts the absorbed energy into ATP by catalyzing a bond between ADP and P.
Interpret that chlorophyll in a leaf has different behavior than the isolated chlorophy
In the leaf, chlorophyll is coupled to a series of chemical reactions that use the energy. Isolated chlorophyll behaves like above.
n a population of butterflies, the most common cause of death is being eaten by birds. Individual butterflies that have the ability to store toxins from plants survive better, because birds find these toxins distasteful. Over many generations, the average amount of toxins stored in the butterflies increases. Which of the following statements provides the best explanation for this change?
Individual butterflies that could store a lot of toxin survived better than those who couldn't store as much toxin.
The venom of some snakes acts by paralyzing muscles of mammals. If a sufficient amount of venom is injected into a mammal (or human), the mammal/human suffocates. Which step of the respiratory process in mammals does this venom most directly interfere with?
Inhalation of air into the lungs
Explain the Central Dogma.
It provides the basic framework for how genetic information flows from a DNA sequence to a protein product inside cells. information flows in one direction, from DNA to RNA to proteins
Identify the level of a question according to Bloom's Taxonomy
Knowledge, Comprehension, Application, Analysis, Synthesis, Evaluation
Explain the importance of Lignin and Lignin Decomposition on the rise and fall of O2levels during the Carboniferous
Lignin Decop did not allow coal formation and did not allow excess O2 to stay in the atmosphere which increased PS
Identify the differences among the different classes of organic molecules
Lipids: fuel Carbohydrates: found in food used for energy Proteins: bonding Nucleic acids: DNA and RNA
Assess the different outcomes of the great oxygen revolution regarding their consequences for life on earth and for earth's geology and atmosphere.
Minerals formed □ Banded iron oreOzone layer formed □ Protection from UV-lightFree O2 is toxic to cells □ Led to global mass extinctionO2 reacted with Methane (greenhouse gas), removing it from the atmosphere □ Led to snowball ice age (2.4-2.1 bya)Some prokaryotes evolved ways to use O2 □ Leading to evolution of cellular respiration(later) Eukaryotes with chloroplasts □ More effective photosynthesis □ Even higher O2 levels □ (much later) Evolution of multicellular life Generated new niches □ opportunities to diversify
Know the basic functions of cellular structures and organelles (mitochondria, chloroplasts, ribosomes, Golgi apparatus, flagella, endoplasmic reticulum, lysosome, cell membrane, cell wall, nucleus, vesicle, vacuole)
Mitochondria:energy production Chloroplasts:contain chlorophyll, involved in energy production and storage Golgi apparatus: the packaging and distribution center Ribosomes:protein synthesis. VERY small. Found throughout the cell but heavily concentrated on the Rough ER Flagella-movement Smooth ER-involved in lipid and carbohydrate metabolism and detoxification Lysosome-type of vesicle involved in disintegrating and removal of waster Rough ER-covered in ribosomes, site of protein synthesis Cell membrane-semipermeable membrane surrounding the cytoplasm of a cell Nucleus-contains genetic material, the cell's genome. Visible in compound microscope as a circular "shadow" Vesicle-packages Cell wall-found in plants (cellulose) and prokaryotes (peptidoglycan) provide rigid structure Vacuole-water storage, especially important in plant cells
Critique statements about natural selection and evolution with regard to their scientific validity.
Mutations occur randomly. Natural selection sorts among alleles, but it does not create new allelesMutations are random, but natural selection is not ○It is not random which individuals are most likely to survive ○ Natural selection is not goal driven ○ No internal drive for perfection or complexity ○ A trait does not evolve 'because the animal needs it'
Which of the following is not a 'postulate of natural selection'?
Natural Selection is not goal directed
Identify fields of science that rely on observations and modeling more than experiments.
Natural science
You talk with a friend from school about natural selection. Your friend states: "A random process like natural selection could never come up with such great features like our eyes!" Which statement would correct this misconception?
Natural selection is not random, as it is not arbitrary which individuals survive and reproduce and which ones not
Recall the basic function, inputs, and outputs of the light dependent and light independent reactions of photosynthesis. Explain why O2is a by-product of photosynthesis
Overall main function of Photosynthesis: TO MAKE GLUCOSE oLight Dependent ReactionsATP is synthesized - Water is split apart in the process, releasing oxygen as a by-productADP and Water and Sunlight are inputsATP and Oxygen are outputsoLight Independent ReactionsThe ATP is used to build glucose from CO2 and water known as the Calvin CycleATP and Co2 and H20 are inputsGlucose is the outputLight energy (photons) from the sun is turned into chemical energy in the form of electrons by the chlorophyll. These electrons are used to split water and the oxygen is not needed to fuel the Calvin Cycle, thus it is a byproduct.
Describe the steps of clinical testing required before and after approval of a vaccine
Preclinical phase- testing in animals, determining proper doses and drug formulations, test for toxicity -Clinical trial Phase 1 - assess safety in healthy people, lowest effective dose- blind, control treatment w placebo Sample size 30+ -Clinical trial phase 2 Builds on results from phase 1 Measures effects on a more diverse group of people, tries different schedules Sample size - several 100s -clinical trial phase 3 Continues to monitor toxicity , adverse effects . effectiveness to induce immunity in natural setting Sample size 10,000-100,000 - If effective in natural disease conditions - APPROVAL BY FDA (US)- widespread use - Clinical trial phase 4 - Continue to monitor of adverse effects, long-term immunity Takes years to approve
Know the differences between prokaryotic and eukaryotic cells, and between plant and animal cells
Prokaryotes: unicellular, nucleoid, no membrane bound organelles, small Eukaryotes: uni or multicellular, nucleus, membrane bound organelles, large
Explain what residual lung volume refers to and why it exists
Residual volume is the volume that is never exchanged. It is the amount of air left in the lungs after maximum exhalation. Residual volume exists because if not, our lungs would collapse.
.Describe the steps occurring during acquired immune responses
Response to specific pathogens - Takes 4-6 days if pathogen is new to host = primary response - Stored in "memory cells" for future infections fast, strong response Macrophages digest pathogen - Present pathogens peptide to T- and B-cells (TC+BC) - Some TC- "killer Tc" destroy infected body cells that show the peptide (+antigen) - - BC: produce antibodies that attach to antigen antigen can't attach - - macrophages clean up antigen-antibody complex
Know the key characteristics of a scientific explanation
Science focuses only on the natural world and how it works and how it is the way it isFocuses on factsRelies of testing ideas and making observationsChecks and balancesNew perspectives always emerging
Refute common misconceptions about science and scientists Explain how/why diversity among scientists improves the quality of the science that is practiced
Scientists work a lot in groups, not alone
The oxygen revolution had both positive and negative implications for life on Earth. What was a disadvantage of the addition of oxygen to the atmosphere at the time it was initially produced?
Since oxygen is highly reactive, it damaged cells and caused a mass extinction of life. oxygen damage is a problem that any organism has to deal with. At the time of the GOE, existing organisms did not have efficient mechanisms to deal with O2, as they evolved in its absence.
What benefit do cells obtain by using facilitated transport instead of simple (=unfacilitated) diffusion to move material across a membrane?
Some molecules have positive and negative regions (i.e. polarity) that prevent them from moving easily through the membrane; facilitated transport overcomes this problem
.Know the features of Coronaviruses
Spherical in shape with a lipid envelope Glycoprotein spikes give it crown name Pos sense RNA
Differentiate between structural and non-structural proteins Know examples of roles of non-structural proteins
Structural- make up capsid of new virions Non-structural- take over cells protein production make viruses - Make extra copies of viral RNA - Assemble new virus particles - Block ribosomes from translating host mRNA
