Biology Test 4

at what elevation do bar headed geese fly?

7000 meters

ventilation

movement of air in and out of the lungs (between external environment and respiratory surface)

cooperative binding of hemoglobin

- hemoglobin consists of four prosthetic heme groups that can bind one O2 each, as each individual O2 molecule binds, it increases the affinity of the next heme group for the additional O2 molecule - also works in reverse for O2 offloading - results in a sigmoidal dissociation curve

properties of oxygen transport molecule

- needs to have high affinity in lungs to grab oxygen readily- needs to have low affinity in body to release oxygen to tissues quickly

steps in mammalian respiration

1. inhalation (brings air inside) 2. O2 diffuses to RBC in lungs 3. O2 binds to blood pigments (hemoglobin) inside RBC 4. RBC are transported throughout the body via the circulatory system and O2 is released from hemoglobin and diffuses to cells in the body 5. O2 used in cellular respiration 6. CO2 diffuses to blood 7. CO2 dissolves into blood (not bound to blood pigment) 8. blood transports CO2 (and RBC without O2) to lungs 9. CO2 diffuses into air through exhalation

surface area of alveoli

150 m^2 (half a tennis court)

Hypothesis vs Theory vs Law

A hypothesis is a statement that can be tested. It addresses small problems or a specific set of phenomena. Scientific theories are general principles explaining a large set of phenomena. Theories are built on large bodies of evidence and encompass multiple hypotheses. Theories can be disputed. A law is a mathematical relationship or principle that is consistently found to be true.

Hypothesis vs. Theory

A hypothesis is either a suggested explanation for an observable phenomenon, or a reasoned prediction of a possible causal correlation among multiple phenomena. In science, a theory is a tested, well-substantiated, unifying explanation for a set of verified, proven factors.

A Left shift in Oxyhemoglobin Dissociation Curve

A left shift will increase oxygen's affinity for hemoglobin. Higher affinity of HB for O2

quarternary protein structure

A number of polypeptide chains linked together, and sometimes associated with non-protein groups to form a protein.

high affinity

hemoglobin's ability to effectively bind to oxygen in lung

low affinity

hemoglobin's ability to release oxygen quickly into the body

How does altitude affect air pressure?

Air pressure decreases as altitude increases

How do the circular processes of photosynthesis and cellular respiration result in carbon cycling within ecosystems?

CR produces CO2 and water which are used in PS to make O2 and glucose which CR uses

carbon cycling

Carbon comes into the living world through the plants, algae, and bacteria that take in atmospheric carbon dioxide to perform photosynthesis. Animals obtain their carbon from these photosynthesizing organisms. The carbon cycle is completed when carbon moves back into the atmosphere in the form of carbon dioxide, which is produced naturally through two processes:the respiration of living things and the decomposition of them following their death.

Which part of an amino acid is always acidic?

Carboxyl functional group

hydrophilic amino acids

Charged side chains: Histidine, arginine, Lysine, Glutamate, Asparagine

how does the structure of the respiratory system facilitate gas exchange?

Gas exchange occurs in the lungs between the alveoli and a network of tiny blood vessels called capillaries, which are located in the walls of the alveoli. The walls of the alveoli actually share a membrane with the capillaries in which oxygen and carbon dioxide move freely between the respiratory system and the bloodstream.

What function do ion gradients have within cells?

Gradients are used to store energy

function of hemoglobin

In red blood cells, carries oxygen from the lungs to body's tissues and returns carbon dioxide from tissues back to lungs. It also maintains the shape of red blood cells.

Why did O2 levels fall during the Permian?

Land masses formed a super-continent which led to a dryer climate and a reduction in photosynthesis which led to the reduced burial of carbon and then O2 dropped as more carbon entered cellular respiration. Fungi which were able to decompose lignin evolved, decreasing the burial of carbon. As carbon levels increased, O2 levels dropped because CO2 was able to form.

What led to increased O2 levels during the Carboniferous?

Large plant life led to an increase in photosynthesis, and the burial of carbon removed it from the carbon cycle, leaving excess O2 in the atmosphere as it was unable to form CO2

respiratory surface

Moist surface across which gases are exchanged between animal cells and the external environment.

how does oxygen affinity of hemoglobin decrease in the body?

PCO2 is increased, CO2 is dissolved in H2O, makes a lower pH and a higher temperature - causes a left shift (lower affinity)

why does human hemoglobin not work at high altitudes?

PO2 is too low for hemoglobin to bind with oxygen in lungs to allow for sustained work- at 100 meters PO2 is 13 kPa- at 8000 meters PO2 is 4.6 kPa

why do oxygen transporters have a complex affinity?

PO2 levels change from lungs to body and vice versa

About 5 million years ago a mutation arose in the gene encoding the alpha1 subunit of hemoglobin in a bar-headed goose that resulted in the high altitude Hb. As discussed in class, this mutation converted an CCU codon in the mRNA (messenger RNA) into a GCU codon.What, if any, amino acid change resulted from this mutation? (Amino acid key chart)

Pro to Ala

translation

Process by which mRNA is decoded and a protein is produced

What is the purpose of residual lung volume?

Residual lung volume keeps the alveoli open even after maximum respiration which allows for continual gas exchange to occur between breaths

Explain similarities/differences among amino acids

Similar: -all amino acids share a common backbone differ: -amino acids differ in the R-group that is attached to the backbone

Function of 2,3-BPG

Stabilizes the unbound state -> in the deoxy state R shift! Detaches when third tetramer binds O2 Increases as part of high altitude compensation By helping at unloading oxygen, it can compensate for anemia by allowing a greater proportion of oxygen to perfuse into the tissue to counter act a lowered level of overall Hb Binds to HbF less strongly than HbA Mutations in the 2,3 BPG binding pocket can decrease affinity for it and therefore increase affinity for O2

lung capacity

The amount of air the lungs can hold

What is the death zone?

The death zone is above 26,000 feet above sea level. There is not enough oxygen there to sustain life. Insufficient oxygen prevents humans from remaining there longer than 48 hours.

what is the difference between partial pressure in the atmosphere and partial pressure in the lungs?

The partial pressure of oxygen in the atmosphere is much greater in comparison to the lungs, creating a pressure gradient; this allows oxygen to flow from the atmosphere into the lungs during inhalation. The air we breathe is our "real" atmosphere.

How does amino acid sequence relate to the overall shape of a protein?

The primary structure of a protein — its amino acid sequence — drives the folding and intramolecular bonding of the linear amino acid chain, which ultimately determines the protein's unique three-dimensional shape.

why do oxygen transporters need to have complex affinity?

They need to take up oxygen in the lungs (high affinity) and release oxygen in the body (low affinity).

what is the function of a gene

To code for a particular sequence of amino acids in order to make a specific protein.

Theory vs. Law

a scientific theory is an in-depth explanation of the observed phenomenon. A law is a statement about an observed phenomenon or a unifying concept

hypothesis

a supposition or proposed explanation made on the basis of limited evidence as a starting point for further investigation.

hydrophobic amino acids

amino acids with long alkyl side chains. Alanine, Leucine, Isoleucine, Valine, Phenylalanine. More likely to be found in the interior of proteins

parts of an amino acid

amino group, carboxyl group, R group

Vital Capacity (VC)

amount of air exhaled after a maximal inspiration (during heavy breathing)

Tidal Volume (TV)

amount of air inhaled or exhaled with each breath under resting conditions

theory

an explanation using an integrated set of principles that organizes observations and predicts behaviors or events

where does a death zone occur?

anywhere above 8000 meters

no oxygen bond during cooperative binding

bent or tensed state

Elevation of Mt. Everest

between 8,800 and 8,900 meters

where is hemoglobin least saturated at a low PO2?

body

acidic and basic amino acids

can make ionic bonds and interact strongly with water, are STRONGLY polar

About 5 million years ago a mutation arose in the gene encoding the alpha1 subunit of hemoglobin in a bar-headed goose that resulted in the high altitude Hb. As discussed in class, this mutation converted an CCU codon in the mRNA (messenger RNA) into a GCU codon.What, if any, alteration in the function of the goose hemoglobin is likely to result from this mutation?

change from tense to relaxed quaternary structure, resulting in a left-shifted Hb-O2 dissociation curve

oxygen-hemoglobin dissociation curve

describes the percentage of hemoglobin saturated with oxygen at any given PO2 - has a sigmoidal shape - hemoglobin affinity increases with increasing PO2 levels

which of the following is NOT an adaptation in birds for the high energy demand of flight?

downy feathers that trap lots of air around the skin of the bird

cooperative binding of hemoglobin

each successive oxygen bound to hemoglobin increases the affinity of the other subunits, while each successive oxygen released decreases the affinity of the other subunits

RNA polymerase

enzyme that links together the growing chain of RNA nucleotides during transcription using a DNA strand as a template

scientific explanation

explanation based on the application of accepted scientific methods, allows testable predictions to be made

oxygen bond during cooperative binding

flat or relaxed state

why did coal formation stop?

fungi evolved which were able to break down lignin, preventing the burial of carbon and formation of coal from carbon and other organic molecules

types of amino acids

hydrophobic, hydrophilic, acidic, basic

relate oxygen - hemoglobin curve to partial pressure of oxygen in lung and body:

in the lung: (PO2 of about 10-15 kPa) hemoglobin is 100%; high affinity in the body: (PO2 of about 4-6 kPa) percentage of hemoglobin drops to about 30%; low affinity

ecological level of organization

interactions between organisms and their environment (lack of predation, break down of lignin)

molecular level of biological organization

involving structure/behavior of molecules (organic molecules, atp synthase, ETC)

structure of hemoglobin

is a four globular subunits (2 alpha, 2 beta) and 4 heme groups (containing iron)

how does oxygen move from the lungs into the blood?

it moves via diffusion from an area of high concentration to an area of low concentration

Right shift of the oxygen dissociation curve means

less affinity of Hb for O2

where is hemoglobin most saturated at a high PO2?

lungs

how does PCO2, pH, temperature, and 2,3 - BPG change the tertiary and quaternary structure of hemoglobin

molecules are charged (polar), when they attach to charged amino acids on outside of hemoglobin subunits, they change the hemoglobin structure and could change function

where does most matter in organic carbons come from?

most matter in organic carbons come from CO2 in the air

secondary protein structure

occurs when the sequence of amino acids are linked by hydrogen bonds

why can a change in amino acid sequence change the 3D structure of the protein?

one change may cause another molecule to be written in genetic code in place of the original code- tertiary structure depends on the spatial dispersion of both hydrophobic and hydrophilic r groups; may spread out or pull together to change overall 3D shape

polar amino acids

one side is slightly more negative than the other

How did lignin affect atmospheric O2 levels?

organisms were unable to decompose lignin, which kept carbon buried, and led to the formation of coal. This led to an excess of O2 in the atmosphere as CO2 could not form.

migration path of Bar Headed Geese

over the Himalayas from India to Mongolia

What is the difference between the percentage of gas in the atmosphere and its partial pressure?

partial pressure is the portion of total gas pressure exerted by a gas rather than by other gases in the mixture

Describe the differences in atmospheric gases between sea level and the Himalayas

partial pressure of O2 (PO2) is lower on Mt. Everest than it is at sea level. This is because O2 makes up the same percentage of the air molecules at high altitudes, but the total number of air molecules there is lower than at sea level

organismal level of organization

physiology of organisms, how they work? (reproduction, more respiration leading to larger body size)

cellular level of organization

processes performed by cells (photosynthesis, cellular respiration, fermentation, gradients)

evolutionary level of biological organization

related to change over time (natural selection)

a mutation happens in the gene for a particular protein, leading to the substitution of one amino acid for another. Which of the following substitutions is most likely to result in a change in the function of the protein?

replacing a negatively charged AA with a positively charged AA

primary protein structure

sequence of amino acids

sigmoidal curve

shows slow and then rapid growth that slows back down when approaching the carrying capacity

function of respiratory system

supply the body with oxygen to be used in cellular respiration and dispose of carbon dioxide

transcription

synthesis of an RNA molecule from a DNA template

partial pressure

the contribution each gas in a mixture of gases makes to the total pressure

A hydrophobic amino acid R group (side group) would be found where in a protein?

the inside of a protein

gas exchange

the process by which oxygen is transported to cells and carbon dioxide is transported from cells, O2 is moved from the air into the blood and CO2 is moved from the blood into air

what is the advantage of unidirectional air flow over bidirectional air flow in a respirator system? As a result of unidirectional flow...

there is less mixing of fresh and "used" air, which lowers the PO2 in the bidirectional air flow

how do transcription factors regulate the expression of geese?

they influence the likelihood that an enzyme will attach to the promoter region of a gene

tertiary protein structure

three-dimensional folding pattern of a protein due to side chain (R group) interactions

Alveoli

tiny sacs of lung tissue specialized for the movement of gases between air and blood, part of the lung in which gases are exchanged

What is the function of transcription during protein synthesis?

to make a copy of the genetic information

Residual Lung Volume (RLV)

volume in lungs after maximum expiration

promoter region of DNA

where RNA polymerase attaches and where initiation of RNA begins