Biology 1500 Test 4

Explain how the circular processes of photosynthesis and cellular respiration result in the cycling of carbon within ecosystems.

Cellular respiration releases carbon dioxide into environment, photosynthesis pulls carbon dioxide out of atmosphere

. Explain the two reasons for an imbalance in this cycle that led to the increased O2 during the Carboniferous.

• Increased photosynthesis

• buried carbon-removed from cycle

Describe the hypothesized reasons for the decline in O2 during the late Permian

Because trees falling down caused carbon to become trapped underground, slowing down photosynthesis and celluyl

Explain the importance of Lignin and Lignin Decomposition on the rise and fall of O2 levels during the Carboniferous

1. Evolved in early trees and allowed for bigger plants because of the structural benefits

2. Could not be decomposed

3. allowed for coal formation from buried carbon

Explain where most of the matter in organic carbons comes from

AIR

Recall elevation of mt everest

8800 M

recall reason for death zone

• Insufficient Oxygen

• High winds and low temps

• Body uses oxygen faster then it can replenish it

• less O2 in atmosphere

Where does the death zone occur

8000m

Recall the migration path of Bar Headed Geese and which feat makes it remarkable

Migrate from India to Mongolia

Elevation at which they fly

Function of mammalian respiratory system

Oxygen moves into blood, co2 moves out of blood into air

List steps of mammalian respiratory system

1. Inhalation

2. O2 diffuses to red blood cells

3. O2 binds to hemoglobin

4. Co2 diffuses into blood

5. O2 used for Cellular respiration

6. Blood transports co2 to lungs

7. Co2 is exhaled

Gas exchange

Exchange of Co2 and O2 in an organism

Tidal Volume

Amount of air moving in and out of lungs with each respiratory cycle

Vital Capacity

Greatest volume of air that can be expelled from lungs after one deep breath

Alveoli

Air sacs in lung allows for rapid gas exchange

Describe how the structure of our respiratory system facilitates gas exchange

Large folded surface= large surface area for diffusion to take place

Explain what residual lung volume refers to and why it exists

• Used air

• there must always be air in lung, if no air, alveoli can stick together and won’t open back up to take in air

Compare the atmosphere we breathe (at sea level) and the atmosphere in our lungs, and explain the reason for the difference

Sea level: Po2= 21KPA. PCO2= 0.04 KPA

In lungs: Po2= 13KPA. PCO2= 5 KPA

All depends on volume of gas exchange

Describe differences in atmospheric gasses between sea level and the Himalayas

O2 at sea level is 3X higher then Himalayas

Differentiate between the concentration (or percentage) of a gas in the atmosphere and its partial pressure

Depending on the altitude the partial pressure of gas varies

Higher altitude= lower partial pressure

Explain similarities/differences among amino acids

Same bases

different R groups

Primary protein structure

Linear Amino Acid sequence

Secondary Protein Structure

hydrogen bonds between backbones of nearby Amino acids cause either a helix or sheet form

Tertiary Structure

Caused by interactions between R groups, determine 3D structure

• Chemical bonds form between distant parts of chain causing the 3d shape

Quaternary Structure

Interactions between separate chains

Describe how classes of amino acids influence their chemical interactions

They have different repulsions and attractions based on their makeup

Hydrophobic Amino acids

Tend to aggregate, end up on interior of protien

Hydrophilic polar Amino acids

• One end of R group slightly more negative then other

• Form H bond with each other within water

Hydrophilic basic/ acidic amino acids

• Strongly polar either + or -

• Usually on outside of protein

• form bonds with each other

Explain why a change in an aa-sequence may change the 3D structure of a protein

the AA sequence codes with what it will react with. Shape determines function

Basic Function of hemoglobin

• Transports O2

• Binds to O2

Structure of hemeglobin

• Contains 4 globular subunits (2 alpha, 2 beta)

• Contains 4 heme groups

explain the basic properties required of an O2 transport molecule, i.e. why transporters need to have complex affinity

• High Affinity is needed to effectively bind O2 in lung

• Low affinity is needed to release o2 in tissues

• Complex affinity is needed because you need to have both high and low affinity

Interpret O2- Hb dissassociation curve

has a sigmodial shape, Hb affinity increases with increasing PO2 levels

define high and low affinity in the context of Hb and O2

Low affinity O2 won’t bind easily

Gets released easily

explain how a left- or right-shift of the binding curve represents a change in affinity

Left is high affinity

Right is low affinity

connect molecular changes during O2 binding to cooperative O2 binding properties of Hb

The O2 and hemoglobin binding process starts out slow but as O2 bonds to hemoglobin it is easier for more O2 to bind (Party analogy)

Explain how the O2 affinity of Hb decreases in the body, incl. which factors contribute to this decrease and how this facilitates the release of O2 in the body

• Decreases because of release of Oxygen

• factors include lower partial pressure of O2

• Lower affinity, cannot hold O2 easily

summarize how pH, PCO2, temperature, and 2,3-BPG change the tertiary and quaternary structure of Hb and thus its O2 affinity.

Co2, H+ and 2, 3 BPG are polar charged

When attached to charged AA on the outside of heme subunits they can change heme structure

change if single AA unit can change function

explain why human Hb does not work sufficiently at high altitude, by relating PO2 at low and high altitude to the O2 Hb dissociation curve.

Does not work at high altitude because PO2 is too low for heme to effectively bind

At 100m PO2 is 13 KPA in lungs vs 8000m PO2 is 4.6 KPA

Know key characteristics of a scientific explanation

1.    Science is about understanding, not facts.

2.    Science focuses on the natural world, not supernatural.

3.    Science relies on testing ideas by figuring out explanations.

4.    New evidence is being acquired and old ideas are being revised.

5.    Science is for the community, relies on diversity and different prospective.

Differentiate between a hypothesis and a formal scientific theory

Hypothesis is made before research, theory uses evidence to support claim

Identify fields of science that rely on observations and modeling more than experiments.

Psych

Physics

Explain how/why diversity among scientists improves the quality of the science that is practiced

Diversity makes it so there are many different ideas and hypothesis

ventilation

Breathing process