Unit 6 Rainforests - Biology

Homeostasis

Maintenance of a stable internal environment despite external changes

Dynamic steady state

Condition where the body maintains balance through constant adjustments, not perfect equilibrium

Set point

Target value the body tries to maintain for a regulated variable

Negative feedback

A response that counteracts a change to return a variable to its set point

Positive feedback

A response that amplifies a change, increasing the original stimulus

Thermoregulation

Maintenance of stable internal body temperature

Endotherm

Organism that regulates internal body temperature using internal mechanisms (warm-blooded)

Ectotherm

Organism whose body temperature changes with environmental temperature (cold-blooded)

Hypothalamus

Brain region that regulates temperature, hunger, thirst, and circadian rhythm

Effector

Organ or cell that carries out the response in a feedback loop

Input

Signal that carries information about a variable to the control center

Integration

Process where the brain compares input to a set point

Output

Signal sent from control center to effectors

Vasodilation

Widening of blood vessels to release heat

Vasoconstriction

Narrowing of blood vessels to conserve heat

Shivering

Muscle contractions that generate heat

Sweating

Release of fluid that cools the body through evaporation

Insulin

Hormone that lowers blood glucose by promoting glucose uptake into cells

Glucagon

Hormone that raises blood glucose by signaling liver to release glucose

Pancreas

Organ that produces insulin and glucagon

Positive feedback in childbirth

Process where contractions increase hormone release, which increases contractions

Negative feedback in temperature

Body responses that return temperature to normal when it rises or falls

ATP

Adenosine triphosphate, universal energy currency of the cell

Adenine

Nitrogenous base found in ATP, DNA, and RNA

Ribose

5-carbon sugar component of ATP

Phosphate group

Functional group containing phosphorus and oxygen that stores energy in ATP

ATP structure

Adenine + ribose + 3 phosphate groups

AMP

Adenosine monophosphate (1 phosphate)

ADP

Adenosine diphosphate (2 phosphates)

ATP hydrolysis

Breakdown of ATP into ADP + Pi releasing energy

Pi

Inorganic phosphate released when ATP is broken down

Potential energy in ATP

Energy stored in bonds between phosphate groups

ATP synthase

Enzyme that produces ATP using proton gradient energy

Chemiosmosis

Movement of H⁺ ions through ATP synthase to generate ATP

Proton gradient

Difference in H⁺ concentration across a membrane

Electron transport chain

Series of proteins that transfer electrons and pump protons

Cellular respiration

Process that breaks down glucose to produce ATP

Aerobic respiration

Cellular respiration that requires oxygen

Anaerobic respiration

Energy production without oxygen, less ATP produced

Glycolysis

Breakdown of glucose into pyruvate in the cytoplasm

Cytoplasm

Location where glycolysis occurs

Pyruvate

3-carbon product of glycolysis

Net ATP from glycolysis

2 ATP produced per glucose

NADH

Electron carrier that stores high-energy electrons

Pyruvate oxidation

Conversion of pyruvate into acetyl-CoA in mitochondria

Mitochondrial matrix

Site of pyruvate oxidation and Krebs cycle

Acetyl-CoA

2-carbon molecule that enters Krebs cycle

CO2 release

Waste product formed during pyruvate oxidation and Krebs cycle

Krebs cycle

Series of reactions that produces electron carriers and CO2

Citric acid cycle

Another name for Krebs cycle

FADH2

Electron carrier produced in Krebs cycle

Krebs cycle ATP yield

2 ATP per glucose

NADH from Krebs cycle

6 NADH per glucose

FADH2 from Krebs cycle

2 FADH2 per glucose

Oxidative phosphorylation

ATP production using ETC and chemiosmosis

Inner mitochondrial membrane

Location of electron transport chain

Oxygen role in respiration

Final electron acceptor forming water

Water formation

Oxygen combines with electrons and H⁺ to form H2O

ATP yield total

About 30–38 ATP per glucose depending on efficiency

Glycolysis yield

2 ATP per glucose

Krebs cycle yield

2 ATP per glucose

ETC ATP yield

Up to 32 ATP per glucose

Fermentation

Anaerobic process that allows glycolysis to continue without oxygen

Low oxygen condition

Triggers fermentation instead of aerobic respiration

Energy efficiency

Aerobic respiration produces more ATP than anaerobic processes

Glucose

Primary fuel molecule used in cellular respiration

Cellular respiration equation

Glucose + oxygen → CO2 + water + ATP

Active transport

Movement of substances against gradient using ATP

Sodium potassium pump

Protein that uses ATP to pump Na+ out and K+ into cells

Neuron function

Relies heavily on ATP for ion gradients

Muscle contraction

Process powered by ATP and actin-myosin interaction

Myosin

Motor protein that interacts with actin during contraction

Actin

Protein filament involved in muscle contraction

Protein synthesis

Process of building proteins using amino acids

tRNA

Transfers amino acids to ribosome during protein synthesis

ATP in protein synthesis

Provides energy to attach amino acids

LUCA

Last Universal Common Ancestor of all life

Universal molecules

ATP, DNA, RNA, proteins found in all life forms

Photosynthesis

Process that converts CO2 and water into glucose using light energy

Equation of photosynthesis

CO2 + H2O + light → glucose + O2

Chloroplast

Organelle where photosynthesis occurs

Thylakoid membrane

Site of light-dependent reactions

Stroma

Site of Calvin cycle in chloroplast

Grana

Stacks of thylakoids in chloroplast

Chlorophyll

Pigment that absorbs red and blue light, reflects green

Pigments

Molecules that absorb specific wavelengths of light

Absorption spectrum

Range of light wavelengths absorbed by pigments

Carotenoids

Accessory pigments that absorb additional wavelengths

Light-dependent reactions

Stage of photosynthesis producing ATP, NADPH, and oxygen

Photosystem II

Complex that splits water and releases electrons

Photolysis

Splitting of water into oxygen, protons, and electrons

Electron transport chain in photosynthesis

Transfers electrons and pumps protons in thylakoid membrane

Photosystem I

Re-energizes electrons to produce NADPH

NADPH

Electron carrier used in Calvin cycle

Calvin cycle

Light-independent reactions that produce G3P from CO2

Carbon fixation

Process where CO2 is attached to RuBP

RuBP

5-carbon molecule that binds CO2 in Calvin cycle

Rubisco

Enzyme that catalyzes carbon fixation

G3P

3-carbon molecule used to form glucose

Reduction phase

ATP and NADPH convert 3-PGA into G3P