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Biology 213 > Test 2 study guide > Flashcards

Test 2 study guide Flashcards

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1
Q

What are the energy sources for autotrophs and heterotrophs?

A
  • autotrophs - sun; example plants
  • heterotrophs - others
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2
Q

What are the carbon sources for photoautotrophs? For chemoheterotrophs?

A
  • photoautotrophs - inorganic molecules, CO2
  • chemoheterotrophs - other organic molecules
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3
Q

What is photosynthesis?

A

converting solar energy to chemical energy

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4
Q

What are the light dependent reactants, needed structures, and products?

A
  • light dependent reactants - H2O and light; also NADP+ and ADP plue phosphate
  • structures - thylokoid, PSII (P680), and PSI (P700)
  • products - ATP, O2, NADPH, H+
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5
Q

What are the Calvin cycle reactants, needed structures, and products?

A
  • light independent/calvin cycle - CO2, ATP NADPH, RuBP (5-C)
  • in the stroma (inside chloroplast outside thylokoid)
  • produce - sugar/glucose, ADP, Pi, NADP+, RuBP
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6
Q

In what organ and organelle does photosynthesis occur?

A

leaf

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7
Q

Where do the light reactions and Calvin cycle occur?

A
  • light reactions - membrane of thylokoid
  • Calvin cycle - in the stroma
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8
Q

Be able to identify the structures of chloroplasts

A
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9
Q

What are photosynthetic pigments?

A

molecule that obsorbs light

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10
Q

What is a primary photosynthetic pigment? Which one is it?

A
  • green
  • chloroplast A is required for light reactions to occur (directly starts reactions)
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11
Q

What is an accessory photosynthetic pigment? Which ones are they?

A
  • accessory pigments shuttle energy, provide protection from harmful light, broaden spectrum
  • chlorophyll b, carotenoids (xanophylls and carotens)
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12
Q

What is a photosystem?

A

photosystems are a light capturing unit, light harnest complex reaction center

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13
Q

Distinguish between PS II and PS I

A
  • PSII comes first (680 wave length)
  • PSI comes second ( 700 wave length)
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14
Q

Which color of light is least efficient for photosynthesis? Most efficient? Why?

A
  • Green is reflected (least efficient)
  • blue, violet and red is best (these colors are absorbed)
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15
Q

What is the equation for photosynthesis?

A

sun + 6 CO2 + (12) H2O → 1 C6H12O6 + 6 O2 + (6 H2O)

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16
Q

What is cyclic electron transport? What is its energy yield?

A
  • Cyclic
    • no electron source
    • PSI
    • ATP
    • no NADPH
    • no oxygen produced
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17
Q

What is noncyclic (linear) electron transport? What is its energy yield?

A
  • Linear
    • electron source H2O
    • PSII and PSI
    • ATP and NADPH
    • O2 produced
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18
Q

What is photolysis? Why is it important?

A
  • light energy used indirectly to split water molecules
  • Important
    • help with H+ gradient
    • source of elctrons
    • generate oxygen
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19
Q

Which photosystem is photolysis associated with? Is it cyclic or noncylic?

A

PSII, noncyclic or linear

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20
Q

What are the 3 phases of the Calvin cycle? What is happening to the carbon chain in each phase? Where is energy required? Is the process anabolic or catabolic?

A
  • 3 phases of the Calvin cycle
    • fixation (carbon fixation)
    • reduction (electrons)
    • regeration of CO2 acceptor (RuBP)
  • carbon chain in phase
    • carbon fixation
      • CO2 (1 carbon) + RuBP (5 carbon) with RIBISCO (carbolase/oxidase)→6 carbon (unstable)→3 carbon (PGA) and 3 carbon
    • reduction
      • phosphoglycerate (use of ATP and NADH) 2-G3P → glucose and 10 G3P to be cycled back through
    • regeration
      • regeneration of RuBP with use of ATP
  • Anabolic
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21
Q

What is photorespiration?

A
  • use of ATP and oxygen to release CO2
  • decreasing rate of photosynthesis
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22
Q

Compare and contrast CAM and C4 plants

A
  • Both
    • close stomata
    • dry hot environment
    • fix CO2 twice
    • calvin cycle (metabolic pathway for c-3 plants)
    • pep carboxylase has an affinity for CO2 over oxygen
  • C4
    • 2 cells used for metobolic pathway (mesophyll and bundle sheath)
    • C-4 organic acid oxylacitate
  • CAM
    • 1 cell used for metobolic pathway (mesophyll)
    • 2 times of the day for CO2 fixation
    • C-4 organic acid
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23
Q

Make sure you have a good understanding of the following:

  1. the nature of light and the absorption spectrum
  2. redox reactions and the use of H+ and electron transfer
  3. NADPH and how it relates to oxidation and reduction
  4. Phosphorylation and decarboxylation
A
  • the nature of light and the absorption spectrum
    • travel in two forms - wavelenth or photon
    • the shorter the wavelength (violet) the higher the energy
    • the longer the wavelenth (red) the lower the energy
    • ROY G BIV
  • redox reactions and the use of H+ and electron transfer
    • redox reaction - a chemical reaction involving transfer of electrons
    • reduction- gaining electrons
    • oxidation - loss of electrons
    • H+ and electron transfer - the ion gradient in the chloroplast (inside thylikoid is high and in the stroma is low)
  • NADPH and how it relates to oxidation and reduction
    • during photosythesis the NADP+ is the final electron acceptor and is reduced to NADPH
  • Phosphorylation and decarboxylation
    • Phosphorylation - A phosphate group is transferred from ATP to glucose, the bond of glucose break and it is rearranged through
    • decarboxylation - The removal of CO2 from a molecule
24
Q

Describe the dermal tissue system (epidermis and periderm (cork/cortex)).

A
  • epidermis - outer covering of herbaceous plants
  • periderm - protective layer in woody plants that forms the outer bark in older stems and roots after the epidermis splits and is lost
  • cork - (secondary tissue) cork cells on the outside that are dead at maturity and have a water proof material (suberin)
25
Q

Describe the ground tissue system.

A
  • composed most of the plant body
  • found in mesophyll in leaves, cortex of roots and pith and cortex in stems.
    • cortex - a cylinder of ground tissue that may contain parenchyma, collenchyma, and sclerenchyma cells
    • contains cells specialized for storage, photosynthesis, and support=metabolic functions
  • in stems of dicots:
    • pith - ground tissue internal to the vascular tissue in stems
    • cortex - ground tissue external to the vascular tissue in stems
  • in roots:
    • endodermis - innermost layer of cortex that regulates passage of substance from soil into vascular cylinder via the casparian strip
26
Q

Describe the structure and function of the vascular tissue system (xylem and phloem).

A
  • conducting system that extends throughout the plant body
  • xylem - tissue that conducts water and solutes
  • phloem - tissue that conducts sugars
  • complex tissue - composed of many cell types: tracheids (water conducting), vessel elements (form vessels), fibers (support), parenchyma cells (only living cells in xylem).
  • two types of xylem water conducting cells tracheids and vessel elements are dead at maturity
  • trachids are found in the xylem of all vascular plants
    • long, pointed cells that have joined, overlapping ends and pits between the cells for water exchanged
    • gymnosperms (cone bearing plant) have only tracheids and no vessel members
  • vessel elements:
    • vessel may be three or four feet long or only inches long
    • cells join end to end with their end walls dissolved out or with holes forming perforation plates
    • a stack of vessel elements is called a vessel
  • sugar conducting cells of phloem
    • phloem transports the carbohydrates synthesized during photosynthesis and provides support
    • sieve-tube elements - cells that join end to end to form long sieve tubes. conducting elements of the phloem thta transport sugars from the leaves to the rest of the plant
      • nucleus disappears and plastids, mitochondria shirnk and cytoplasm is reduced to a thin peripheral layer
      • contain sieve plates which are the porous end walls that allow fluid to flow between cells along the sieve tube
    • companion cells - cells connected to sieve-tube cells
      • assist and regulate the metabolism of their adjacent sieve-tube members
      • contains plasmodesmata
        • plasmodesmata - cytoplasmic connections between companion cells and its sieve tube member
27
Q

Distinguish between tracheids and vessel elements in xylem; sieve elements (with companion cells) in phloem

A
  • trachids are found in the xylem of all vascular plants
    • long, pointed cells that have joined, overlapping ends and pits between the cells for water exchanged
    • gymnosperms (cone bearing plant) have only tracheids and no vessel members
  • vessel elements:
    • vessel may be three or four feet long or only inches long
      • cells join end to end with their end walls dissolved out or with holes forming perforation plates
      • a stack of vessel elements is called a vessel
  • sugar conducting cells of phloem
  • phloem transports the carbohydrates synthesized during photosynthesis and provides support
  • sieve-tube elements - cells that join end to end to form long sieve tubes. conducting elements of the phloem thta transport sugars from the leaves to the rest of the plant
    • nucleus disappears and plastids, mitochondria shirnk and cytoplasm is reduced to a thin peripheral layer
    • contain sieve plates which are the porous end walls that allow fluid to flow between cells along the sieve tube
  • companion cells - cells connected to sieve-tube cells
    • assist and regulate the metabolism of their adjacent sieve-tube members
    • contains plasmodesmata
      • plasmodesmata - cytoplasmic connections between companion cells and its sieve tube member
28
Q

Distinguish between the types of plant cells. Know characteristics of each. Know what cells are in each type of tissue

A
  • cells - basic structural and functional unit
    • plant cells structures
      • chlorophyll for photosythesis
      • cell walls around the cell membrane
      • primary cell wall - thin and flexible composed of cellulose
      • cells held together by pectin (sticky polysaccharide) which yields a stron yet flexible plant body
  • some plants have secondary wall which contains lignin. produced when the cell is matur and stops growing to strengthen the wall
  • parenchyma cells are elongated or sherical with a large central vacuole
    • have thin and flexible primary walls
    • lack secondary walls
    • parenchyma cells carry out most metabolic processes: respiration photosytnthesis, storage, and secretion
    • found in he pith and cortex of stems and mesophyll of leaves
    • parenchyma cells store plant materials such as starch, oil droplets, water and even salts
    • retain the ability to divide and differentiate
  • collenchyma cells are elongated grouped in strands, living and maturity, an dwill often have chlorophyll
    • the cell walls (composed of cellulose and pectin) have marked flexible uneven thickening
    • they lack secondary walls
    • these cells provide flexible support without restraining growth
  • sclerenchyma cells are rigid with primary and secondary cell walls that function in support
    • dead at functional maturity
    • two types of sclerenchyma cells: fibers and sclereids
      • fibers: long pointed cells with thick pitted cell walls with rather small lumen
        • very elastic and after stretching will snap back to its original shape
      • sclereids
        • usually occur in small cluster or a solitary cell
        • cellwalls are thicker than fibers. shape is often cubical but may be quite variable
29
Q

What do trichomes do?

A
  • trichomes - epidermal outgrowth that a single or multicellular
  • can help with inscet defense
  • root hairs are examples of trichomes
30
Q

What is a root hair?

A

thin tubular extension of a root epidermal cell that increases the absorptive capacity of roots

31
Q

Distinguish between herbaceous and woody plants

A
  • herbaceous - non woody plant whose aerial parts die back to the ground at the end of the growing season. these plants do not produce secondary tissue. have stems with primary growth
  • woody : aerial parts (trees and shrubs) persist all year. produces hard lignified secondary tissue (cell walls of secondary tissues (vascular and cork cambiums) contain lignin. have stems with primary and secondary growth
32
Q

Discuss the differences among annuals, biennials, and perennials, and give an example of each.

A
  • annuals: herbaceous plants that grow, reproduce and die in one year or lexx
  • biennials: herbaceous plants that take two years to complete their life cycle
    • first year is used to make large amounts of carbohydrates that are stored
    • second year is when the flower appears and reproduction occurs
  • perennials: herbaceous or woody plantsthat have the potential to live for more than two years
    • herbaceous perennials sometimes die back during the harsh season and grow new aerial parts each year
    • woody plants are perennials with permanent woody stem. their aerial parts do not die back but they may drop their leaves
33
Q

Distinguish between deciduous and evergreen

A
  • decidious - shed their leaves each year
  • evergreen - shed their leaves over a long period of time
34
Q

Distinguish between primary and secondary growth

A
  • primary growth - takes place in the apical meristem; an increase in stem and root length (taller)
    • all plants have primary growth
    • produces the entire plant body in herbaceous plants
    • produces youn, soft shoots and roots in woody trees an dshrubs
  • secondary growth - takes place at lateral meristems; an increase in grith of a plant
    • occurs in gymnosperms and woody dicots
  • as primary growth adds leaves and lengthens the stems and roots in younger regions of a plant, secondary growth thickens stems and roots in older regiond where primary growth has stopped.
35
Q

Distinguish between apical meristems and lateral meristems

A
  • apical meristems - are located at the tips of roots and shoots and at the axillary buds of shoots
  • lateral meristems - areas of localized cell division on the side of a plant that give rise to secondary tissues; extends along the entire length of the stems and roots except the tips
36
Q

Discuss variation in leaf form, including simple versus compound leaves, leaf arrangement on the stem, and venation patterns. Know leaf anatomy!

A
  • Complexity:
    • simple leaf - a leaf with a single blade
      • simple leaves may have margins/edges that are:
        • entire: no indentation/smooth edge
        • lobed: deep indentation (sinuses)
        • toothed: serrated edges, very shallow indentations
        • undulate: wavy margins
      • OR compound leaf: the blade is divided into two or more leaflets
        • palmate: the leaflet diverge from a single point
        • pinnate: the leaflets are arranged along an axis
        • doubly compound leaf: the blade consists of multiple leaflets AND each leaflets is divided into smaller leaflets
  • leaf arrangement on stem
    • alternate: one leaf at each node
    • whorled: three or more leaves grow at each node
    • opposite: two leaves grow at each node
  • venation patterns:
    • parallel: veins run parallet (monocot)
    • pinnately netted: major veins braching off in succession along the entire length of a midvein (central vein)
    • palmately netted: several major veins radiating out from one point
  • anatomy - consist of a blade and petiole
    • leaf blade: the broad, flat portion of the leaf
      • contains many chloroplasts and provides a broad, flat surface for capturing light = carries out photosynthesis
    • petiole: the stalk that attaches the blade to the stem
37
Q

Describe the major tissues of the leaf (epidermis (cuticle, stomata), photosynthetic ground tissue (mesophyll~palisade and spongy layer), xylem, and phloem), and label them on a diagram of a leaf cross section.

A
  • epidermis -
    • upper epidermis thicker cuticle than lower epidermis to prevent water loss
    • lower epidermis usually contains more stomata for gas exchange and to reduce water loss
    • trichomes: har-like structures covering the epidermis of many leaves
      • functions to reduce water loss by retaining a layer of moist air next to the leaf and reflecting sunlight, deterring herbivores by secreting stingin irritants
  • mesophyll: photosynthetic ground tissue in a leaf, that is sandwiched between the upper and lower epidermis
    • the palisade mesophyll in the upper part of the leaf; primary function is photosynthesis
    • the spongy mesophyll in the lower part of the leaf; the loos arrangemtn allows for gas exchange.
  • vascular tissue of each leaf is continuous with the vascular tissue of the stem
    • veins are the leaf’s vascular bundles
      • xylem: conducts water and disolved minerals; usually located in upper part of a vein
      • phloem: conducts dissolved sugars; usually confined to lower part of a vein
    • each vein in a leaf is enclosed by a protective bundle sheath, bost prominent in C4 plants
      • bundle sheaths are composed of parenchyma or sclerenchyma cells
38
Q

Compare leaf anatomy in dicots and monocots

A

did we talk about this?

39
Q

Relate leaf structure to its function of photosynthesis/reduction in water loss

A
  • The cuticle on the top of the leaf to prevent most of the water loss
  • trichomes to help keep the evaporated water around the leaf longer.
  • palisade meshophyll on top layer of leaf to allow for the most photosynthesis
  • most stomata on the bottom of the leaf to allow for evaporation but a few on the top of the leaf to reduce the amount of evaporation
40
Q

Outline the physiological changes that accompany stomatal opening and closing (what are the steps that cause guard cells to change shape and thereby open and close stomata?)

A
  • StomatalOpening and Closing are Due to Changes in Guard Cell Turgidity.
    • During the day stomata must open for photosynthesis to occur (except CAM plants)
      • When water flows into the guard cells, they become swollen, and the inner walls bend outward, producing a pore.
      • Stomatal opening and closing is triggered by light levels, as well as carbon dioxide concentration within the leaf, dehydration, hormones, and a biological clock
    • Stomata open and close in response to the movement of H+and K+across the guard cells’ plasma membranes
      • Blue light triggers an influx of potassium ions by active transport of H+ through specific channels out of the guard cell, requiring ATP
      • The resulting voltage (membrane potential) drives K+ into the cell through specific voltage gated channels causing the water potential to become negative
      • Water then passes into the guard cells by osmosis and the cell swells (turgid)
      • The stomata close by a reversal of this process. Cell becomes flaccid(limp)
      • (notewhen flaccid: plasma membrane still contacts the cell wall but lacks turgor pressure).
    • Closing stomata occurs as evening approaches and sucrose concentration in guard cells declines as it is converted back to starch (osmotically inactive substance)
      • Water leaves by osmosis and guard cells lose heir turgidity closing the pore
41
Q

Discuss transpiration and its effects on plants.

A
  • enviromental condition -
    • higher humidity decreases transpirations
    • lower humidity increases transpiration
    • wind blows away water vapor faster that would normally cluster around the trichomes
42
Q

Know woody twig anatomy

A

aerial parts (trees and shrubs) persist all year. produces hard lignified secondary tissue (cell walls of secondary tissues (vascular and cork cambiums) contanins lignin

have stems with primary and secondary growth

43
Q

What are the functions of stems?

A

organ of a plant that provides structrual support, conduction, and production of new stem tissue

44
Q

What are some examples of modified stems?

A
  • rhizomes: a horizontal underground stem that bears buds and oftern serves as a storage organ and means of asexual reproduction; e.g. iris
  • tubers: thickened end of a rhizome that is fleshy and enlarged for food storage; e.g. potato
  • bulbs: fleshy underground bud that consists of a short stem with fleshy leaves; e.g. onions and tulips
  • stolons (runners): above ground horizontal stems with long internodes, often have buds that develop into separate plants; e.g. strawberry
45
Q

Label cross sections of woody dicot, herbaceous dicot, and monocot stems, and describe the functions of each tissue. (Notice differences in vascular arrangement!)

A
46
Q

Name the two lateral meristems, and describe the tissues that arise from each

A
  • vascular cambium: single layer of undifferentiated parenchyma cells that adds layers of vascular tissue called secondary xylem (wood) to its interior and secondary phloem to its exterior
  • cork cambium: thin layer of meristematic cells located in the outer bark that replaces the epidermis with periderm, which is thicker and tougher
47
Q

Outline the transition from primary growth to secondary growth in a woody stem. (i.e. how does the vascular cambium begin to form and produce new secondary tissues?). What is the difference between cork cambium and vascular cambium?

A
  • As primary growth adds leaves and lengthens the stems and roots in younger regions of a plant, secondary growth thickens stems and roots in older regions where primary growth has stopped.
  • vascular cambium: single layer of undifferentiated parenchyma cells that adds layers of vascular tissue called secondary xylem (wood) to its interior and secondary phloem to its exterior.
    • Located outside the pith and primary xylem and to the inside of the cortex and primary phloem. (between the bark and wood of a woody plant)
48
Q

Describe the pathway of water movement in plants.

A
  • Bulk flow transport of xylem sap occurs due to the water loss of water by transpiration.
  • Almost all of the water that a plant absorbs is ultimately lost by evaporation.
  • Very little water is lost across the cuticle; nearly all is lost through the stomata.
  • Light, wind, and low humidity increase water losses.
  • Transpiration is tied to the upward movement (pull) of water through xylem
  • Transpiration also results in evaporative cooling.
  • Further, transpiration results in the uptake of minerals from the soil as plants take in water to replace that which is lost.
49
Q

Define water potential.

A
  • Water movement can be explained by a difference in water potential.
    • Water potential (Ψ): quantity of a physical property that predicts the direction in which water will flow
    • Potential refers to the water’s capacity to perform work when it moves from higher water potential to lower water potential
    • Measure Ψ in a unit called Megapascals (MPa).
      • Pure water is given a free energy value of 0 megapascals (MPa) because its free energy cannot be measured directly.
    • Effected by solute concentration
      • Ψs is the solute potential (osmotic potential)
        • Solutes effect direction of osmosis
        • Ψs of pure water is O MPac.Water with dissolved materials (solutes) has a negative effect (lowers the water potential) on ᵠby binding water molecules. E.g. 0.1M solution of sugar has Ψs of -0.23MPa
        • Negative water potential is created when solutes are added because they bind water molecules resulting in fewer free water molecules (reduced capacity) to move and do work.
      • Water moves from an area of higher water potential (less negative) to an area of lower water potential (more negative).
        • Flaccid plant cell is one that is limp and a result of losing water
        • Plasmolysis: in hypertonic environments the cytoplasm shrinks and pulls away from the cell wall
        • Turgid plant cell is one that is very firm and a result of gaining water
50
Q

Explain the roles of tension-cohesion and root pressure as mechanisms responsible for the rise of water and dissolved nutrient minerals in xylem. (adhesion/cohesion/tension, etc)

A
  • Tension-cohesion pulls water up a stem.
  • Tension-Cohesion Hypothesis: proposes that the movement of xylem sap is driven by a water potential difference created at the leaf end of the xylem by the evaporation of water from leaf cells.
    • Evaporation lowers the water potential at the air-water interface (inside the leaves), thereby generating the negative pressure (tension) that pulls water through the xylem.ii.This mechanism is based on an unbroken column of water in the xylem.
    • This column forms because of the cohesionof water due to hydrogen bonding betweenwater molecules.
      • Cohesion: linking of like molecules, often by hydrogen bonding
    • The adhesionof water to the walls of the xylem cells (also due to hydrogen bonding) also maintains the column of water.
      • Adhesion: clinging of one substance to another
51
Q

Describe the pathway of sugar translocation in plants.

A
  • Translocation: transport of products of photosynthesis via phloem tissue, e.g. from leaves to actively growing parts and storage.
  • Sugar produced during photosynthesis is converted to sucrose for transportation within the plant body.
    • Solutions may move in either direction in the phloem, but always from sources (area of excess sugar) to sinks (areas of storage).
      • Source: a plant organ that net producer of sugar by photosynthesis or breakdown of starch (e.g. leaves –the main source, tuber, bulb)
      • Sink: a plant organ that is a net consumer or depository of sugar (e.g. growing roots, buds, stems, and fruits)
  • The Pressure-flow Hypothesis Explains Translocation in Phloem.
52
Q

Discuss the pressure-flow hypothesis of sugar translocation in phloem

A
  • Pressure-flow hypothesis proposes that building of positive pressure at the source and reduction of that pressure at the sink cause sap to flow from source to sink.
    • At the source, sucrose is moved into the companion cells of the phloem, utilizing ATP as an energy source.Companion Cells: cells connected to sieve-tube cells.
      • Assist and regulate the metabolism of their adjacent sieve-tube members.
      • Sugars move from companion cells to the sieve tube member through the plasmodesmata.
    • Water follows by osmosis (higher water potential in xylem to lower water potential in sieve tube phloem cell) increasing the pressure within the sieve tube member, thereby pushingthe solution through the phloem.
      • Sieve-Tube Elements: cells that join end to end to form long sieve tubes. Conducting elements of the phloem that transport sugars from the leaves to the rest of the plant.
    • At the sink,sugar is moved out of the sieve tube members, and water follows osmotically.
53
Q

Distinguish between taproot and fibrous root systems.

A
  • Taproot system: a root system consisting of a prominent main root with smaller lateral roots branching off it
    • A taproot develops directly from the embryonicradical in a seed
    • Obtain water located deep underground
    • Found in most dicots and gymnosperms
  • Fibrous root system: a root system consisting of several adventitious roots of approximately equal size that arise from the base of the stem
    • adventitious: plant organ that arises from an unusual position on a plant
    • Obtain water located relatively close to the soil surface such as light rain water
    • Found in most monocots
54
Q

Label cross sections of a primary dicot root and a monocot root, and describe the functions of each tissue.(root cap, root hair, epidermis, cortex)

A
55
Q

Describe the casparian strip.

A

Casparian Strip: a band of waterproof material around the radial and transverse walls of endodermal root cells

Biology 213 (8 decks)

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