Author Notes

hello hello! thank you for visiting my unit 3 cram sheet on cellular energetics !! all info in this cram sheet is derived from the AP daily videos and some of my teacher lecture notes :)

• like my cram sheets? check out my others via profile <3 (all units will be done b4 exam??!)

• external resources tht r similar to a section will be linked at the end!!!!! gl studying!!!

╭ Other Resources :

:: cararra ﹒﹒ 23 min ap bio review video based from the campbell biology 11th edition textbook!

:: sticky science﹒﹒short, bite-sized review videos in the form of reels from a previous ap bio student who got a 5 on the AP exam!

:: khan academy ﹒﹒the entire unit 3 course from khan academy!!

:: fiveable ﹒﹒ reviews unit 3 with articles and quizzes for you to practice your knowledge on!

﹙✦﹚﹒﹒abbreviations r used throughout this sheet :]

﹙3.1-3.3 - Enzymes﹚

✦﹒enzymes are biological catalysts that speed up biochemical reactions

• enzymes often end in -ase (catalase, sucrase, lactase, amylase )

• has an active site that specifically interacts with a specific substrate (like a lock and key)

  • this initiates a reaction (synthesis or digestion of substrate)

• changes in shape causes denaturation

  • active site can no longer bind to specific substrate

  • denaturation can be reversible in some cases

✦﹒every enzyme has a optimum range

• range in which reaction occurs the fastest

• reaction rate changes when optimum range isn’t maintained

✦﹒there are many factors that affect the enzyme—

how factors affect the enzyme activity in graphical form

• pH levels

  • if outside optimum range → dec in enzyme activity, later denatured

• temperature

  • inc in temp outside optimum range will inc activity, then later denature

  • dec in temp outside optimum range will slow activity, never denature

• enzyme concentration

  • inc → inc activity

  • dec → dec activity

• substrate concentration

  • inc will inc, and later stay constant to a certain point

• inhibitors, which can be either noncompetitive or competitive

  • noncompetitive - inhibitor binds to allosteric site, causing change in enzyme shape

    

  • competitive - inhibitor competes with substrate, potentially alters reaction rate depending on amt

    • more inhibitors than substrate → slowed reaction

    • less inhibitors than substrate → normal reaction

    • can be reversible - enzyme is not affected by inhibitor binding

    • can be irreversible - enzyme is affected by inhibitor binding, permanently losing functionality via change in shape

    

✦﹒in a lab regarding enzymatic activity, there will be variables

• positive control - confirms a known effect

• negative control - confirms a result of absence in what is tested

• control variable - aspects of experiment that are left unchanged, the baseline data

╭ Other Resources :

:: amoeba sisters ﹒﹒ goes over enzymes in general, briefly touches on factors that affect its activity near the end

﹙✦﹚﹒understanding the factors that affect enzyme reaction rate is key!!! def gonna be a frq/mcq asking about control variable

﹙3.4 - Cellular Energy﹚

✦﹒2nd law of thermodynamics states that ”entropy (disorder) must increase”

• nature favors the process of going from order → disorder

  • exception is living things; they tend to go from disorder →order

    • every energy transfer increases disorder in the universe

✦﹒pathways in biological systems r sequential to allow for a more controlled and efficient transfer of energy

✦﹒metabolism is the sum of reaction in an organism

• energy is constantly moving

• catabolic reactions involve breaking down; lrg → small

  • also defined as exergonic

  • ex: cellular respiration, as sugars are broken down to ATP

  • another ex— ATP Hydrolysis (ATP + H₂O→ ADP + Pi + free energy)

• anabolic reactions involve building up; small → lrg

  • also defined as endergonic, as energy is used

  • ex: photosynthesis uses sun energy to build sugar from CO₂,

  • another ex— ATP Synthesis (ADP + Pi + free energy → ATP + H₂O)

﹙3.5 - Photosynthesis﹚

✦﹒photosynthesis is the biological process that captures light energy from the sun to produce energy

• evidence supports the claim that prokaryotic photosynthesis by organisms, such as cyanobacteria, was responsible for the early production of O₂ in the atmosphere

✦﹒light dependent reactions captures light energy by light absorbing molecules called pigments (chlorophyll)

• helps transform light to chemical energy

• light has electrons, powering NADP+ to NADPH

• photosystem - light-capturing unit in a chloroplast’s thylakoid membrane

  • has photosystem I and II (PSI, PSII)

  • passes energy to electron transport chain

visual of light dependent reactions

✦﹒calvin cycle is the light independent reaction in which captured energy powers the production of carbs

• uses ATP, NADPH + CO₂ to make carbohydrates

﹙3.6 - Cellular Respiration﹚

process overview on cellular respiration

✦﹒electron transport chain (ETC) is a metabolic pathway tht efficiently transfers energy frm electrons to a proton gradient

• electrons come frm electron carriers (NADH, FADH₂)

• active transport of proteins happen here

✦﹒oxidative phosphorylation is a process that uses ETCs, chemiosmosis, and ATP synthase to make ATP

• NADH and FADH₂ lose electrons to ETC (“oxidative”)

• ATP synthase does ADP + Pi → ATP (“phosphorylation”)

• in cellular respiration, the decoupling of this process frm the ETC generates heat

  • proton gradient is not being used by ATP synthase

  • heat can be used by endothermic organisms to regulate body temp

﹙3.7 - Fitness﹚

✦﹒fitness is the ability of the cell to survive and reproduce, often increased by variation

• can provide organisms w/the ability to respond to a variety of environmental stimuli

• can provide organisms w/fitness advantages under changing environment conditions