Biology Module 3

Energy Carriers

• deliver usable “on demand” energy

• required for metabolic activity

Adenosine triphosphate (ATP/ADP)

• powers almost all activities in the cell

• _________ can release energy when it loses a terminal phosphate, thus becoming ________ diphosphate (____).

• During photosynthesis, light energy from the sun is used to convert ___ back into ___.

• During cellular respiration, chemical energy in sugars is used to convert ___ back to ___.

Autotrophs (producers)

• Obtain energy from the nonliving environment

• things that do photosynthesis: plants, algae, and certain bacteria

Heterotrophs (consumers)

• Exclusively obtain energy by consuming other organisms

• ex. humans + other animals

• glucose + oxygen → carbon dioxide + water + energy

Photosynthesis

• the metabolic pathway that transforms light energy from the sun into the chemical energy of food molecules (sugars)

• Carbon Dioxide + water + sun’s energy → glucose + oxygen

• two stages: light reactions and calvin cycle

Light Reactions

• start photosynthesis by absorbing light, splitting water molecules, and producing energy carriers for the next stage.

• begin with chlorophyll

Calvin Cycle

• uses energy from ATP (from light reactions) to convert CO2 into glucose (sugar).

• aka carbon fixation

• takes place in chloroplast

Chlorophyll

• absorbs light energy, which drives the synthesis of energy carriers

Stomata

• pores on a leaf that open and close to allow carbon dioxide to enter

Transpiration

• the process plants use to pump water to, and out of, leaves using stomata

• does not use energy and transports up to hundreds of thousands of pounds of water every day

• water through xylem

Xylem

• uses 3 properties of water to transport it without using energy\

  • cohesion- water molecules stick together

  • adhesion- water molecules stick to the sides of transport structures

  • evaporation- all movement is powered by evaporation

• tiny, skinny straw

• dead cells

Phloem

• transports nutrients(food)

• connected cells

• cells are living

• turns to xylem

Trichome

• a structure in plants that absorbs water through its leaves

• present in airplants

C3 Photosynthesis

• standard photosynthesis → most efficient

• Calvin cycle + light reactions

C4 Photosynthesis/plants

• photosynthesis for humid + high light intensity habitats

• makes more sugar in high sunlight environments

• delay calvin cycle

• When humid and transpiration halts, light energy can be stored until transpiration resumes.

Crassulacean Acid Metabolism (CAM) Photosynthesis

• least energy efficient, calvin cycle at night

• Photosynthesis for dry, arid habitat

• succulents

• keep stomata closed more often to retain water

• water conservation

Cellulose

• a plants main structural component

  • make cell body + walls

• not digestible by animals, only bacteria and fungi have the ability to get energy from it.

• stores carbon dioxide

Starch

• houses glucose(sugar/energy), which plants use for food

Rubisco

• present during Calvin Cycle

• the enzyme that incorporates CO2 into plants during photosynthesis

• responsible for the rearrangement of carbon dioxide

Cellular Respiration

• chemical energy in sugars is used to convert ADP back to ATP.

• creates a large amount of ATP, or energy

• 3 Stages- glycolysis, krebs cycle, oxidative phosporation

• photosynthesis steps backwards

Glycolysis

• first stage in cellular respiration

• enzyme-catalyzed reactions break sugar molecules into smaller molecules, generating ATP

• glucose breakdown

• outside of mitochondria

• no energy required, anaerobic process

• creates pyruvate: 1 glucose → 2 pyruvate

Krebs Cycle

• second step of cellular respiration, an aerobic process

• takes place in the mitochondria

• molecules produced by glycolysis are broken to release carbon dioxide, generating energy carriers (some ATP and many molecules of NADH)

• breaking pyruvate down to generate a lot of energy

• fills one end of the mitochondria with high-levels of electrons

Oxidative Phosphorylation

• final step of cellular respiration, an aerobic process

• takes place in the mitochondria

• uses oxygen to produce ATP in quantity

Pyruvate

• the final product of glycolysis (the initial breakdown of glucose)

• 1 glucose molecule → 2 _______

Aerobic Respiration

• requires oxygen

• produces much more ATP

• Krebs Cycle and Oxidative phosphoration are this type of process

• high concentrations of blood supply + mitochondria in this type of tissue

Anaerobic Respiration

• does not require oxygen

• glycolysis is this type of process

Fermentation

• anaerobic process

• begins with glycolysis(break-down of glucose), followed by post glycolytic reactions(pyruvate) whose only role is to help perpetuate glycolysis.

• Supports ATP Production through Glycolysis When Oxygen Is Low or Absent

Lactic Acid

• a result of mitochondria not having enough oxygen to go through the Krebs cycle.

• When there isn’t enough O2 present the pyruvate goes through fermentation resulting in _____ _____.

Ammonia

• is produced from the breakdown of amino acids (Proteins).

ATP Synthase

• turbine to create ATP

• flow of electrons to make turbine turn and uses that energy to add a

  third phosphate to ADP, making it ATP

• uses the energy from the previous processes to create ATP