HCS 2202 Exam 2

asexual reproduction

generation of genetically identical copies of a plant through mitosis

meiosis

reduction in chromosome number by half, separation of diploid to make haploid

fertilization (syngamy)

recombination of chromosomes to original number, fusion of haploid to make diploid

diploid

2n, contains a pair of homologous chromosmes

haploid

1n, contains one set of homologs

how sexual reproduction creates variability

crossing over, independent assortment, fertilization

crossing over

exchange of corresponding segments of DNA between chromatids of homologous chromosomes

possible combinations of independent assortment

n², for diploid find n first

outcrossing

additional genetic variation if gametes come from genetically different parents

alternation of generations

multicellular diploid generations alternate with multicellular haploid generations in a single life cycle

gametophytes

haploids, sexual, 1n, ends with gametes forming a zygote

sporophytes

diploid, asexual, 2n, ends with spores being formed through meiosis

male flower cell lifecycle

microsporocytes (2n), microspores (n), microgametophytes (n), microgametes (n)

pollen grain

a mature male microgametophyte with three cells, 1 tube cell and 2 sperm cells, monocots have one furrow dicots 3

female flower cell lifecycle

megasporocyte (2n), megaspore (n), megagametophyte (n)

double fertilization

one sperm fertilizes the central cell which becomes the endosperm and one sperm fertilizes the egg cell

pollination

the process by which pollen in transferred from the anther to the stigma by wind, insects, birds, etc.

self pollination

pollination of a flower with pollen from the same flower or another flower on the same plant (ex. wheat, rice, tomato)

cross pollination

pollination of a flower with pollen from a different plant (ex. corn, apple, cotton)

genetic self incompatibility

prevents self-pollination or pollination by a clone

imperfect flower

enhance cross pollination by only having either male or female flower parts

monoecious

have separate male and female flowers both located on the same plant

dioecious

an individual plant with only male or female flowers

dichogamy

maturation of stamens and pistils at different times

protandry

stamens produce pollen before stugmas are receptive

protogyny

stigmas are receptive before pollen is shed

Bees co-evolution

visual and olfactory, blue and yellow

birds co-evolution

red and orange, ordorless

butterflies co-evolution

visual and olfactory, red, blue, and yellow, sweet odor

moths

nocturnal, white, sweet odor

beetles

dull colors, smell over sight, smell of decay

bats

dull colors, strong odor

wind

no nectar, dull colors, incomplete flowers

double ferilization

seeds containing embryo and endosperm

endosperm

contains starch, oil, protein, the energy needed developing embryos

embryogenesis

establishes the body plan for the plant, following fertilization, the first cell division of the zygote is asymmetric

plumule (embryo)

embryonic shoot/bud

epicotyl (embryo)

stem like axis above cotyledons

hypocotyl (embryo)

stem like axis below cotyledons

radicle (embryo)

embryonic root

scutellum (embryo)

cotyledon in grass embryo

coleoptile (embryo)

sheath over the plumule in monocots

seed coat/testa

ovule wall/integument

micropyle

opening in ovule where sperm enters via pollen tube

hilum

scar where ovule was attached to ovary

fruits

a mature ovary, usually contains seeds, may or may not include additional flower parts

pericarp

fruit wall, develops from mature ovary wall

exocarp

outer layer

mesocarp

fruit flesh

endocarp

tough innermost layer

fleshy fruits

simple, aggregate, or multiple

dry fruits

indehiscent or dehiscent

simple fruits

develop 1+ united carpels

aggregate fruits

numerous carpels from 1 gynoecium

multiple fruits

gynoecia of more than 1 flower

indehiscent

seeds remain in fruit after shedding

dehiscent

mature ovary wall breaks open, freeing the seeds

epigeous

cotyledons above ground

hypogeous

cotyledons remain in soil

seed dormancy

when a seed does not germinated even in favorable conditions to avoid vivipary

BD - after ripening

gradual loss of dormancy in dry seeds (winter annual)

BD - light promotion

light (usually red) requirement to germinate

BD - light inhibition

germination is inhibited by exposure to sunlight

BD - stratification

exposure to cold before germination

BD - high temps

exposure to high heat for germination

BD - chemical promoters

parasitic plants germinate in response to compounds released from hosts

productivity

total dry matter accumulation

relative growth rate

increase in dry matter per unit time

yield

total dry matter accumulation in harvestable unit

harvest index

dry weight of harvestable unit/total plant dry weight

photoautotrophs

use light energy to synthesize complex organic compounds from small inorganic molecules

light reactions

conversion of light energy into energy stored in chemical bonds

thylakoids

contain chlorophyll

grana

stacks of thylakoids

stroma

fluid surrounding thylakoids

chlorophyll A

bluish green, pigment and reaction center, absorbs violet blue and red

chlorophyll B

yellowish green, only pigment

accessory pigments

chlorophyll b, beta carotene, lycopene, xanthophylls

photosystems

large complexes of proteins and pigment molecules located on the thylakoid membrane that capture light energy

reaction center

contains a special pair of chlorophyll A molecules and a primary electron acceptor

photosystem 1

provide e- to make NADPH, replace missing electrons, more chlorophyll A

photosystem 2

replenish e- of p1, reduces H2O to O2, 2e-, and 2H+

dark reactions

carbon fixation, reduction, regeneration, need 3 ATP and 2 NADPH to fix 1 CO2, output is 1 G3P

carbon fixation

incorporates CO2 into 5 carbon sugar, RuBP, using rubisco, splits into 2 3C molecules, inputs are 3 CO2, 9ATP, 12e- and outputs are 1 G3P

redcution

input of high energy phosphate group from ATP and 2e- from NADPH to make G3P

regeneration

regen 5 carbon RuBP with ATP

allocation

G3P is converted to fructose and glucose in mesophyll cells and sucrose is made from the two in the cytoplasm

diffusion

net movement of molecules from high concentration to low

osmosis

diffusion of water across a semipermeable membrane, always follows solute

facilitated diffusion

transport proteins allow hydrophilic molecules and ions to pass without energy, carrier or channel proteins

active transport

movement of solute against the concentration gradient, only carrier proteins

sources

mature leaves, roots, rhizomes, tubers, bulbs

sinks

meristematic regions, flowers, fruits, seeds, rhizomes, tubers, bulbs

sieve tube elements

long distance food transport, relies on companion cells, lack nucleus

sink strength

sink size x sink acitivity

phloem repair

p-protein stops bleeding, callose, a carb, protects wound as scab, phloem eating insects sela puncture wound without the former two

glycolysis

glucose is converted to pyruvic acid, input is 6C glucose and 2ATP, output is 2 3C pyruvate, 2 ATP, and 4 e-

citric acid cycle

high energy e- are removed which releases CO2, input is 2 pyruvate and output is 6CO2, 20 e-, 2 ATP

oxidative phosphorylation

electron carriers donate electrons to etc, powers chemiosmosis, input is e- and O2, output is H2O and 28 ATP

final electron acceptor

oxygen