Unit 3 - Sonoran Desert

annuals

plants that die every year and must be replanted.

perennials

plants that come back every year

desertification

land degradation where the fertile landscape turns arid, with soil quality, vegetation, water, and wildlife all decreasing

cellulose

molecule that makes up most of a plant’s biomass. made of long chains of glucose

roots

obtain H2O for plant

leaf

part of the plant where sunlight hits to initiate photosynthesis

stem

aids in transport and provides structure to grow upwards`

flower

responsible for sexual reproduction/pollination

fruit

responsible for seed dispersal

6CO2 + 6H2O → C6H12O6 + 6O2

photosynthesis equation

cell wall

provides protection, structure, and shape for cell. made of cellulose

chloroplast

organelle that performs photosynthesis and contains chlorophyll

vacuole

stores water in cell and creates turgor pressure

turgid

rigid plant, vacuoles full of water

flaccid

wilted plant, vacuoles lack water

passive transport

transport that does not require any ATP/energy input. dependent on potential energy differences

diffusion

movement of molecules from high to low concentrations in order to reach equilibrium

osmosis

movement of water from less concentrated → more concentrated across a semipermeable membrane

Moves from higher WATER CONCENTRATION to lower water concentration

dilute

solvent high, solute low

concentrated

solute high, solvent low

turgor pressure

exerted by water in a plant cell against the cell wall

phloem

carries nutrients around plant, controlled via osmosis

xylem

carries water through dead cells from roots to leaves

cohesion

water sticks to each other via hydrogen bonds

adhesion

water sticks to other molecules

capillary action

cohesion + adhesion, movement of liquid through narrow space

stomata

gaps in leaf that open and close via guard cells

open stomata

water leaves, guards cells are turgid, H2O is abundant in the environment

closed stomata

water conserved, guard cells flaccid, and H2O scarce in environment

rate of water loss

how fast water transpired increases with an increase in the gradient

transpiration

evaporation from plants

water use efficiency

how much water a plant keeps to itself (carbon gain / H2O lost)

relative growth rate

how fast a plant grows (biomass gained / time)

photosynthesis

process where plants create glucose from CO2 and solar energy

respiration

process where organisms convert glucose to ATP

gradient

a difference in 2 things

potential energy

energy of position or charge

kinetic energy

energy of motion

ground state

state where electrons are in a stable form. electrons are close to the nucleus.

excited state

electron is in a higher energy state or orbital. electrons are further away from the nucleus and have more potential energy, making them more unstable.

C-O bond

the most stable carbon bond, with the lowest potential energy. it can be reduced to more unstable forms.

C-C bond

the middle-stable carbon bond. it can be either oxidized or reduced.

C-H bond

the most unstable carbon bond, with the highest potential energy. it can be oxidized to become more stable.

reduction

H is added, more unstable

• gaining electrons/energy

oxidation

oxygen is added, more stable

• Losing electrons/energy

redox

a paired reaction where one molecule is reduced (gains an electron) and another is oxidized (loses an electron)

reducing agent

causes reduction, gets oxidized

oxidizing agent

causes oxidation, gets reduced

cuticle

waxy secretion (fats, waxes) at the top of a leaf

palisade cells

located under cuticle in a column-shaped organization, tissues full of chloroplasts where photosynthesis takes place

spongy mesophyll

located under palisade cells, this is where gas exchange takes place. products of photosynthesis and water gather here.

thylakoid

located inside chloroplast, this is where light-dependent reactions take place.

• Disk-like sacs suspended in the stroma

calvin cycle

light-independent reactions: a series of reactions that occur in the stroma, where CO2 and chemical energy is converted into sugar.

nucleus

where we find the DNA in eukaryotes in the form of linear chromosomes

mitochondria

the site of cellular respiration (ATP production!)

photosystem 2

light excites electron, chlorophyll → chlorophyll+, electron bounces around and travels to the ETC

water splitting

process where water is broken down into O2, H+, and electrons. this is necessary to replenish the lost electron from chlorophyll+

electron transport chain

electron moves through membrane, loses energy as it is used to power the H+ pump, where there is the active transport of H+ ions from the stroma into the lumen

photosystem 1

chlorophyll+ → chlorophyll, re-excited by light, electron from chlorophyll lands on NADP+, which creates NADPH

ATP synthase

enzyme that facilitates the creation of ATP from ADP and P_i, lets H+ ions flow from the lumen into the stroma via passive transport

fixation

CO2 is added to RuBP, which is broken down by Rubisco to create PGA

reduction

PGA, along with ATP and NADPH as energy, is converted into G3P, ADP, and NADP+

regeneration

G3P, along with ATP as energy, is converted into RuBP and ADP

6 turns

how many turns for 1 glucose?

3 turns

how many turns to fully regenerate RuBP?

photorespiration

Rubisco can bind to O2 instead of CO2 when it is hot or when there is not enough intercellular CO2

C4 photosynthesis

photosynthesis that modifies the first step of the Calvin Cycle. Fixation and the rest of the cycle occur in different cells, separating Rubisco from O2 entirely. 

bundle sheath cells

cells that contain modified chloroplasts that contain no grana. this is where malate is converted back to CO2

CAM photosynthesis

photosynthesis where plants only open their stomata at night, fixing CO2 to malate during the day only and storing malate in vacuoles.

succulents

What types of plants perform CAM photosynthesis?

grasses

What type of plants perform C4 photosynthesis?

niche

a set of environmental conditions and resources that are necessary for a species survival and reproduction

competitive exclusion

the better competitor survives, and the worse competitor goes extinct. there is one winner and one loser.

niche partitioning

species with overlapping resources compromise and thus, they can both persist. the weaker species cedes some of the resource.

temporal

type of partitioning where two species use the same resource but at different times

spatial

type of niche partitioning where two species use a similar resource but in different areas

functional

type of niche partitioning where two species use a similar resource but in different ways

fundamental niche

space an organism could occupy

realized niche

space an organism actually occupies, this accounts for competition with other species

specialists

species that have a narrow niche and need certain requirements to survive. more vulnerable to changes.

generalists

species that can survive with a broad niche/broad range of resources

exponential growth

no limit on resources, population always growing

logistic growth

limited resources constrict population growth, hits carrying capacity and hovers around there

r-selected species

high growth rate, but also high death rate

K-selected species

maintain carrying capacity over time

type 1

survivorship where most survive infancy and live to old age

type 2

survivorship where there is no age-related mortality

type 3

survivorship where most die young, and those who do survive will live a full life to adulthood