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Bio test 2 > Lecture 12a > Flashcards

Lecture 12a Flashcards

1
Q

where do we get energy from?

A

the sun

the chemical elements essential to life are recycled

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2
Q

what are the two major modes of acquiring nutrition?

A

1) autotrophic nutrition
2) heterotrophic nutrition

autotrophs are self feeders whereas heterotrophs are other feeders

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3
Q

what do photoautotrophs do?

A

they convert light energy (sunlight) into chemical energy (sugar) through photosynthesis
- they use c02 from the atomosphere as their source of carbon

plants, algae, cyanobacteria, purple and green sulfur bacteria

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4
Q

what is the order of food chain in both terrestrial and aquatic food chains?

A

primary producers = base of all food chains = autotrophs

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5
Q

what are the two types of photosynthesis?

A

1) oxygenic
2) anoxygenic

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6
Q

what are the two reactions of photosynthesis

oxygenic & anoxygenic

A
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7
Q

what are the four leaf and plant structures aiding photosynthesis?

A

1) mesophyll
2) stomata
3) vascular tissue (found everywhere in the plant)
4) chroloplasts

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8
Q

what is the structure of the leaf tissue?

A
  • flat and thin creating a large surface area
    leaf tissue consists of:
  • epidermis
  • vascular tissue
  • mesophyll

chloroplasts and stoma are smaller components within the mesophyll and epidermis

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9
Q

what causes the green color on leafs?

A

chlorophyll pigments are found in the mesophyll

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10
Q

how does the leaf reduce dessication?

A

it has a top and bottom epidermis that are coated with a waxy cuticle which helps prevent water from escaping and keeps co2 and O2 from passing through

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11
Q

where does gas exchange happen on the leaf?

A

pores on the leaf called stomata (stoma) located in the lower epidermis

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12
Q

what is vascular tissue?

A

a system of vessels to distribute substances throughout the plant
- from the root to the tip of the leaf

light blue = H2O dark blue = CO2 pink = O2 green = sugar brown = minerals
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13
Q

what is the mesophyll?

A

tissue composed of cells that peform photosynthesis in leaves
- contain a high amount of chloroplasts for photosynthesis

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14
Q

name the structures of this chloroplast

A
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15
Q

how are chloroplasts similar to the mitochondria?

A

they have a double membrane enclosed organelle

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16
Q

what is the fluid inside the inner membrane of the chloroplast called?

A

stroma

contains DNA and enzymes

contains internal called thylakoids
the thylakoids are stacked up to form towers called Granum

17
Q

do chloroplats move?

A

they are non static organelles like the mitochondria - they move along the tracks of the cytoskeleton
- they have a changeable shape and pinch in two - reproducing themselved

18
Q

what is a pigment?

A

substance that absorbs light energy

chloroplasts can convert light energy into chemical energy because they contain pigments

19
Q

where are photosynthetic pigments found?

A

they are found embedded in the thylakoid membranes of chloroplasts
- each pigment absorbs different wavelengths of light and reflect others

20
Q

what are the three types of pigments being reflected?

A

1) chlorophyll a
2) chlorophyll b
3) cartenoids

21
Q

what is the difference between chlorophyll a and b?

A

a:
- key light capturing pigment

b:
- works in conjunction with chlorophyll a

both have a central atom of magnesium

22
Q

what are the two parts to chlorophylls?

A

1) has a porphyrin ring:
light absorbing head of the molecule - magnesium is at the center
2) has a hydrocarbon tail:
interacts with the hydrophobic regions of proteins inside thylakoid membranes of chloroplasts
serves to stablilize the pigment in the thylakoid membrane

23
Q

what are cartenoids?

A

large group of pigments that gives leaves, fruits and vegetables their **yellow-orange coloration **
- the chlorophyll is broken down in response to shorten day lengths and cold temperatures

24
Q

what is the job of cartenoids?

A

have the job of photoprotection:
- absorb and dissipate excess light to prevent damage to the chlorophyll pigments
- prevents the formation of free radicals which could harm the cell

25
Q

what is the wavelength range that photosynthesis falls under?

A

380nm (shorter wavelength but high energy) - 750nm (longer wavelength but lower energy)

26
Q

what do we see when pigments absorb light?

A

we see the wavelengths reflected

27
Q

what color do chlorophyll a and b absorb and reflect?

A

a:
absorb violet-blue and red light
reflects blue-green light
b:
absorb violet-blue and red light
reflects yellow-green light

the only color reflected by the chloroplasts main pigments is the green spectrum

28
Q

what colors do carotenoids reflect and absorb?

A

absorb: violet and blue-green
reflect: shades of yellow and orange

29
Q

what is the basis of photosynthesis?

A

energy transfer

the electron moves into a higher energy level
- only photons absorbed are those whose energy is exactly equal to the energy difference between the ground and excited states of a pigment molecule

30
Q

what happens when the chlorophyll molecule is isolated?

A
  • the excited electron drops back down
  • absorbed energy is released as heat, vibration or light
the photon excites the electron to be able to move over to the next energy shell

although chlorophyll molecules are not isolated in chloroplasts

31
Q

what is inductive resonance?

A

when the light is being transfered and the electrons are getting excited untill they reach a reaction center
- vibration energy is transferred

think of a dance floor and how when one person starts dancing that encourages someone else to dance and then another person and then another person
32
Q

what is a photosystem composed of?

A

composed of a reaction center (electrons are excited and vibrate till they reach here) that is surrounded by several light-harvesting complexes

33
Q

what is the reaction-center complex?

A

organized association of proteins holding a special pair of chlorophyll a molecules

34
Q

how many photosystems are there?

A

two
photosystem II comes before photosystem I

found in thylakoid membranes of chloroplasts

35
Q

what does photosynthesis convert the energy from sunlight into?

A

convert carbon dioxide and water into glucose and oxygen

some of the glucose produces will be used to make ATP in cellular respiration

36
Q

what is carbon fixation?

A

when glucose is synthesized into macromolecules which are incorporated into the tissues of the plant

37
Q

what gets reduced and what gets oxidized in photosynthesis?

A

CO2 gets reduced:
- all the carbon atoms it holds are fixed into sugar
- half of the oxygen atoms go into making sugars and the other half into making water
water gets oxidized :
- oxygen atoms are released as O2 ( gain of oxygen = oxidation )
- hydrogen atoms are transferred to form sugars

38
Q

what is the difference in terms of redox reactions between photosynthesis and cellular respiration?

A

their redox reactions are reversed

the flow of electrons in photosynthesis is reversed

39
Q

what are the two steps in photosynthesis and what do they generate?

A

1) light reactions:
- occurs in thylakoid membranes
- generates O2, ATP and NADPH from light energy and water
2)** calvin cycle **
- light independent reactions ( doesn’t need direct sunlight as it has enough stored ATP to use )
- occurs in the chloroplast stroma
- generates sugar molecules from ATP, NADPH, and CO2

Bio test 2 (9 decks)

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