Module 19 Flashcards
Metabolism, the Environment, and Evolutionary Fitness
Cell Work
moving ,dividing, and transporting substances in and out
Fitness
the ability of organisms to survive and reproduce in a particular environment
What do the laws of thermodynamics describe
How energy behaves in a system
How energy is TRANSFORMED
What is photosynthesis and where is energy stored
Light energy converted to chemical energy
Energy is stored within the bonds of carbohydrates
What is cellular respiration
Energy-rich bonds within carbohydrates are broken, and pack released energy into ATP molecules to do cell work
Molten
Earth had no rocks nor evidence of life
Stromatolites
Layered sedimentary structures produced by microbial communities on shallow sea floors and lake bottoms
Earliest forms of life
prokaryotic; unicellular organisms with no nucleus
How did our earliest life forms evolve
Prokaryotes evolved multiple metabolic pathways
What kind of the pathways did our earliest life forms use and why
Probably a fermentation pathway to generate ATP energy, because our early atmosphere contained little to no oxygen gas
What happened during fermentation
Glucose is only partially oxidized , so only some of the energy held within its chemical bonds is transferred to ATP
Why do we know that fermentation was the process held within our early organisms
It is anaerobic and because nearly all organisms are capable of partially breaking down glucose, telling that this pathway evolved very early in history and maintained.
What carbohydrate is commonly used to store energy
glucose
Aerobic Cellular Respiration
When oxygen is the final electron acceptor of the respiratory electron chain
Anaerobic Cellular Respiration
When any other molecule, such as sulfate or nitrate, is the final electron acceptor of the respiratory electron chain
Where is the electron transport chain located
In the cell membrane
When did anaerobic cellular respiration likely evolve
After fermentation, to harness ADDITIONAL ENERGY from glucose in the absence of oxygen
Why did protein pumps likely evolve
To maintain a neutral pH in early prokaryotes, since the earth’s environment was likely acidic
They pumped out H+ ions/ protons out of the cell
How do protein pumps get energy
From ATP directly or from electron transport, just like in photosynthesis and respiratory transport chains today
What pathways use the electron transport chain
Fermentation, and cellular respiration
Which bacteria evolved the ability to carry out a form of photosynthesis that produces oxygen
cyanobacteria
Type of photosynthesis that produces oxygen
oxygenic photosynthesis
Why didn’t initial forms of photosynthesis not produce oxygen
They didn’t use water as their electron donor, and therefore couldn’t have O2 as a byproduct
How did oxygen begin to accumalate on earth
photosynthesis
What must’ve happen to a cell for it to be capable of oxygenic photsynthesis
It must have incorporated cyanobacteria by endosymbiosis
What is the cyanobacteria, now, in eukaryotic cells
It has evolved into the chloroplast
What, evolutionary wise, is the thylakoid membrane
the internal photosynthetic membrane found in cyanobacteria
What is the stroma of the chloroplast, evolutionarily speaking
cytoplasm of the ancestral cynobacterium
What can photosynthesis produce that is toxic to the cell
reactive oxygen species
Oxygen Catastrophe/ Oxygen Crisis
The accumulation of o2 gas on the atmosphere and the MASSIVE LOSS OF LIFE that occurred
What did O2 in the atmosphere lead to in evolution
New ways to EXTRACT ENERGY from organic molecules
What form of cellular respiration release more energy in the form of ATP
Aerobic cellular respiration
How did new metabolic pathways increase evolutionary fitness of some organisms
Increased ability to survive and reproduce in their environment
What is chlorophyll and what does it do
Chlorophyll is a pigment that absorbs and reflects light
- Reflects green light, which is why they appear green
Anthocyanin
Pigment that reflects red, blue, or purple depending on the pH of its environment
Carotenoids
Pigments that reflect red, orange, and yellow pigments
What kind of carotenoid give carrots their orange color
Carotenes
What kind of carotenoids give yellow-orange pigments
Xanthophylls
How do xanthophylls reduce light energy
They take absorbed light from the chlorophyll and CONVERT THIS LIGHT ENERGY into HEAT, preventing the formation of dangerous reactive oxygen species that are toxic to the cell
What happens to plants that lack xanthophylls in moderate light
They grow poorly or die, because they are not protected from the full range of light energy
Hemoglobin
Molecule in red blood cells in which oxygen is bound to
It transports this oxygen around to cells throughout the body
How do molecules or structure evolve to have diverse roles
They evolve over time through common ancestors
Hemoglobin structure
4 globin subunits
Heme groups
Each globin has a heme group with an iron atom
It reversibly binds one oxygen molecule, allowing the transport of oxygen from the lungs to tissues for respiration
Fetal Hemoglobin
Has higher affinity for O2 than does adult hemoglobin, allowing the fetus to attain sufficient O2
How do variants of hemoglobin differ
In structure and how tightly they bind to oxygen
How do animals who live in high altitudes receive enough oxygen, although their air has less oxygen in it
Their hemoglobins have HIGHER AFFINITY for O2, binding more readily to oxygen than animas at sea level
Myoglobin structure and its effect
It only has one globin subunit and one heme group, so Myoglobin has a higher affinity for O2, binding more tightly to it
Where is myoglobin found and its effect
Found in vertebrae muscles, so hemoglobin in the blood vessels release oxygen to exercising muscles, since the myoglobin readily and tightly gets the O2 molecules
Why is Myoglobin important in muscle cells that depend on aerobic respiration to produce ATP
Myoglobin can quickly release O2 on the onset of activity
Why do deep diving mammals need myoglobin
They load up with O2 at the surface and Myoglobin supplies O2 to produce ATP, when air is not available to them to breath
Increased forms throughout evolution allow for what
Fitness throughout diverse environments.
