Carbon Cycle etc...

Question 1

How do mineral ions in the soil move into the plant?

Answer 1

Diffusion: flow down a concentration gradient into root
Fungal hyphae: symbiotic relationship (fungus absorbs minerals for plant in exchange for sugars)
Mass flow: water flows into plant INTO high solute concentrations by osmosis (creates negative pressure in soil around root); minerals hydrogen bond to water and move passively with water into plant
ACTIVELY
*Protein pumps in root cells (lots of mitochondria) actively transport mineral ions against concentration gradient (like potassium ions) OR *Protein pumps actively pump H+ ions into surrounding soil (these bind to negatively charged ions in soil and diffuse back into root with H+ ions); displaces (forces out) positively charged minerals from clay so they can be absorbed (diffusion) into root cells – this is INDIRECT active transport

Question 2

Root structure/function

Answer 2

Epidermis: protection; root hairs increase surface area for
absorption
Cortex: transports (diffusion) water/ ions to stele (vascular tissue)
Stele
Endodermis/ Casparian Strip: impermeable to water and
ions; controls rate of uptake – must be pumped
Pericycle/ cambium: lateral root development
Vascular bundle
Xylem (X-shaped; water and mineral ion transport from roots
to stems to leaves)
Phloem (phloem = more out/ surrounding xylem; sugar and
amino acid transport)

Question 3

Dicots

Answer 3

Vascular bundles form a ring structure
Xylem is more internal in vascular bundle and more “porous” looking (phloem = outer)

Question 4

Monocots

Answer 4

Vascular bundles are scattered
Xylem is more internal in vascular bundle and more “porous” looking

Question 5

Why do stomata open/close?

Answer 5

When dehydrated, mesophyll cells release abscisic acid, causes guard
cells (around stomata) to LOSE potassium, water follows by osmosis,
decreasing water pressure/making guard cells flaccid = closing stomata
* K+ ions actively transported into guard cells, water follows by osmosis,
guard cells turgid = opens stomata

Question 6

How does CO2 in air affect transpiration?

Answer 6

MORE CO2 in air = decreased transpiration (stomata do NOT need to be open as much to get CO2 in)

Question 7

How does Translocation work?

Answer 7

Sugars (as sucrose)/ amino acids actively transported (companion cells) into phloem tissue (called sieve tubes - at leaves/ stems = SOURCE); water diffuses from xylem into phloem (creating sap); sap volume/ pressure drives sap downward (mass flow); companion cells actively transport organic molecules (sugar stored as starch) into “SINK” (fruit, seeds, roots) and water moves back into xylem (osmosis)

Question 8

Sieve elements

Answer 8

long/narrow and joined together to form long tube; anucleate; thick/rigid cell walls to withstand high pressure; connected by sieve plates (have pores)

Question 9

Companion Cells

Answer 9

loading and unloading of organic
compounds from sieve tubes; increased surface area; lots of
mitochondria and transport proteins; plasmodesmata (connect
cytoplasm to sieve elements)

Question 10

Aphids

Answer 10

Used to calculate translocation rates.

Question 11

Apical Meristems

Answer 11

Adds Vertical Growth
Primary Growth
Primary xylem and Phloem
New leaves and flowers

Question 12

Lateral Meristems

Answer 12

Occurs at cambium
Lateral growth
Secondary growth
Secondary xylem and phloem
Produces bark on trees

Question 13

Auxin

Answer 13

Inhibits lateral buds
Auxin changes patterns of gene expression
stimulates cell elongation
Used for phototropism

Question 14

Pollination

Answer 14

Movement of pollen from anther to stigma

Question 15

Fertilization

Answer 15

Fusion of haploid nuclei

Question 16

PRACTICE DRAWING SEEDS AND FLOWERS

Answer 16

do it bro

Question 17

Seed Germination

Answer 17

1. Absorption of water – production of gibberellic acid (GA/ gibberellin)
2. GA turns on genes that synthesize amylase
3. Amylase hydrolyzes starch (into maltose)
4. Maltose hydrolyzed for glucose (ATP) or polymerized for cellulose (cell wall formation)
5. Cotyledons provide stored food for energy until leaves/photosynthesis
6. Seed coat will eventually rupture and radicle (seed root) will emerge and grow into ground

Question 18

Phytochrome

Answer 18

Pr converted to Pfr in the daylight
Pfr promotes flowering in long day plants
Pfr inhibits flowering in short day plants

Question 19

Long day plants

Answer 19

Burst of light during night of short days

Question 20

Detritivore

Answer 20

organisms that ingest nonliving organic matter/ feces (ingest THEN digest - earthworms)

Question 21

Saprotrophs

Answer 21

organisms that live in/ on nonliving organic matter – secreting enzymes into it to digest it then absorb the digested products (digest THEN ingest – bacteria, fungi)

Saprotrophs recycle nutrients (complex organic compounds broken down into simple, inorganic substances which go back into the soil/ water/ atmosphere) in ecosystems for autotrophs to use to make organic compounds again - heterotrophs also release inorganic substances back into the environment as a byproduct of metabolic reactions/ processing organic compounds (cellular respiration releases CO2)

Question 22

Carbon Cycle

Answer 22

Photosynthesis: CO2 removed from
atmosphere/ water by plants; “fixed” to make organic compounds (sugars, proteins, lipids) = largest flux

Feeding: Heterotrophs obtain organic
compounds by feeding

Cellular respiration: Organisms
breakdown organic compounds to
release energy (and release CO2 and heat
as byproducts)

Decomposition (aerobic):
Saprotrophs break down organic material
and release CO2 (and carbon to soil, air, etc.)
-Decomposition (anaerobic):
Methanogenic archaeans breakdown organic
compounds and release methane (CH4) which forms deposits underground or is oxidized to CO2 and H2O in atmosphere

Saprotrophs inhibited by anaerobic conditions and organic acids produced in anaerobic conditions (lower pH) and organic matter not fully decomposed forms peat (in waterlogged soils) - compressed peat can form COAL (fossil fuel)

Combustion: Burning of fossil fuels/ biofuels releases CO2 into atmosphere (significant increases in CO2 in atmosphere)

Bodies of Water (largest carbon sinks): CO2 dissolves in bodies of water (diffusion) and combines with H2O to form carbonic acid. Carbonic acids dissociates into carbonate ions and hydrogen ions. Hydrogen ions lower pH (acidic). Carbonate ions used by molluscs and corals for shells/ exoskeletons (which can compact to form limestone rock). Increased temps and lower pH cause corals to expel symbiotic algae (bleaching) and cause LESS carbonate ions to be incorporated into shells and exoskeletons so they are weaker too.

Question 23

Sustainable Ecosystems

Answer 23

To be sustainable over LONG periods of time, ecosystems must have:
-Energy availability (light source/ sun)
-Nutrient availability (decomposers) - recycling of carbon, nitrogen, oxygen etc.
-Waste recycling/ Water

Question 24

Greenhouse gases

Answer 24

Absorb IR radiation
Trap and re-emit heat, warming earth

Question 25

Evidence for Evolution

Answer 25

Homologous Structures
DNA Sequences
Fossil Record
Artificial selection/selective breeding
NOT analogous structure

Question 26

Variation in a species due to sexual reproduction

Answer 26

*Crossing over: Prophase I of meiosis when non-sister chromatids (of homologous chromosomes) break at the same
locations and exchange portions of DNA – creating new genetic combinations
*Random orientation/ independent assortment: During metaphase I and metaphase II of meiosis when homologous
chromosomes line up and separate randomly from each other (creates 2n possible combinations of gametes)
*Random fertilization: fusion of haploid gametes (maternal and paternal – 2n possible combinations from each parent)

Question 27

Natural selection and evolution

Answer 27

*Within populations there exist genetic (heritable) variations (mutations, meiosis, sexual reproduction)
*Populations tend to produce more offspring than the environment can support (leading to competition)
*Environmental pressures allow only those organisms best adapted to the environment to survive and reproduce = differential reproductive success (Note: survivors pass on their genes for their favorable traits/ adaptations)
*Over many generations, there is a change in allele frequencies of gene pool of population due to differential reproduction (survival of the fittest)

Question 28

Antibiotic resistance in bacteria as example of natural selection/evolution

Answer 28

*Within population of staph bacteria there exist variations – antibiotic resistant and nonantibiotic resistant
*Population produces more offspring than environment can support
*Staph (in patient) exposed to antibiotic (methicillin) and mostly those with antibiotic resistant gene survive
*Those that survive are able to reproduce and pass on their antibiotic resistance genes to offspring
*Over many generations, most of the population now possesses antibiotic resistant genes (change in allele frequency)
Note: Antibiotic resistance genes can be TRANSFERRED to non-antibiotic resistant bacteria too (via plasmids), but bacteria CANNOT just “decide” to develop resistance when exposed to antibiotics (they either ALREADY have the antibiotic resistant gene or not - BEFORE being exposed to antibiotics)

Question 29

Types of Natural Selection

Answer 29

Stabilizing - ONE, intermediate (middle of the road)
phenotype is favored/ becomes more common (stable
environment with low competition) - human birth weights
Disruptive - TWO, extreme phenotypes favored over
intermediates (fluctuating environment/ seasons)
Directional - ONE phenotype favored over another (gradual
changes in environment - adaptive radiation; ex: peppered
moths)

Question 30

Allopatric speciation

Answer 30

GEOGRAPHIC barriers (rivers, mountains, volcanoes etc.) prevent interbreeding (and exposure to different environmental conditions causes gradual divergence/ change in allele frequencies)

Question 31

Sympatric Speciation

Answer 31

REPRODUCTIVE barriers (not physical barriers) prevent interbreeding. Can be temporal (different timing in reproductive cycles/ periods/ activities so no interbreeding) or behavioral (incompatible courtship behaviors so no interbreeding)

Question 32

Polyploidy

Answer 32

Sympatric speciation can be caused by polyploidy: meiotic failure results in gametes with extra SETS of chromosomes
-More common in plants because can self-pollinate/ reproduce asexually (ex: Allium)- can happen in only one generation (polyploid plants usually larger/ more disease resistant/ have increased longevity)

Question 33

Genetic Drift

Answer 33

Higher in smaller populations
Random or chance events

Question 34

Rates of Speciation

Answer 34

Gradualism: Small, continuous, slow changes in species due to small, slow, continuous changes in environment over long periods of time (transition fossils show evidence of this)
Punctuated Equilibrium: Long periods with stable environment and no appreciable change in species then short periods of rapid evolution (due to fast/ great changes in environment) - gaps in fossil record are evidence of this

Question 35

Bryophyta

Answer 35

No true leaves, roots, stems
No vascularization
Spores
Anchored by rhizoids
Example: moss

Question 36

Filicinophyta

Answer 36

Roots, leaves, stems
has vascularizaton
spores
Leaves are pinnate
Example: ferns

Question 37

Coniferophyta

Answer 37

Roots, leaves, stems
Has vascularization
Seeds in cones
Woody Stems
Example: conifers

Question 38

Angiospermophyta

Answer 38

Roots, leaves, stems
Has vascularization
Seeds in fruits
Have flowers and fruits
Example: Flowers