Author Notes

hello!! welcome to my unit 1 cram sheet of the first unit; chemistry of life!!! majority of my notes r derived frm the ap daily videos and my teacher lectures so yeah!!! enjoy enjoy <33

• like this cram sheet? check out my other cram sheets!!!

• external resources that are similar to a section will also be linked at the end!

╭ Other Resources :

:: cararra ﹒﹒ 25 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!

:: the APsolute recAP﹒﹒22 min review video based on all the topics of unit 1!

:: khan academy ﹒﹒the entire unit 1 course from khan academy!!

:: fiveable ﹒﹒ reviews unit 1 with articles and quizzes for you to practice your knowledge on!

﹙✦﹚﹒﹒abbreviations are used throughout <3

NOTE: for some reason some imgs won’t show up :(( all images will show up on mobile tho :)

﹙1.1 - Structure of Water and Hydrogen Bonding﹚

✦﹒water is composed of oxygen and hydrogen

• the two form a covalent bond, where oxygen and hydrogen share their electrons

  • oxygen and hydrogen are specifically polar-covalent, as of the polarity from the differences in electronegativities

  • oxygen is more electronegative than hydrogen

• water has a hydrogen bond, which is a weak bond interaction btwn negative and positive molecules

• polar molecules are hydrophilic (water-loving)

• non-polar molecules are hydrophobic (water-hating)

  • an example of this includes phospholipids, which are a part of the plasma membrane

✦﹒water has many special properties—

• cohesion is caused by hydrogen bonds btwn molecules of the same type

  • this enables water to have surface tension enables small objects to “float” on water (ex: water striders r allowed to stand on water thanks to surface tension)

  • cohesiveness allows ice to be less dense than liquid water and therefore float on water

• adhesion is caused by hydrogen bonds btwn different types of molecules

  • adhesiveness makes water a universal solvent, being able to dissolve a lot of substances in its liquid state

• has a high heat capacity the provides thermal stability

  • caused frm water’s cohesive property, being able to absorb a lot of thermal energy before changing chemical states, resisting sudden temp changes

• has high latent heat of vaporization, meaning it’ll take a lot of energy to change phases

  • example is human’s sweat; evaporation of sweat leaves a cooling effect thanks to this

• has capillary action, in which water has the ability to move thru narrow spaces due to the forces of adhesion, cohesion, and surface tension

  • movement of water going up is against gravity

  • example - plants use this action ot bring water up frm the roots to the stem

╭ Other Resources :

:: amoeba sisters ﹒﹒ in-depth on the properties of water !!

﹙✦﹚﹒grasping the concept of water’s properties is ideal! be able to provide an example with each too :)

﹙1.2 - Elements of Life﹚

✦﹒living systems req. a constant input of energy

• first law of thermodynamics/ law of conservation of energy states that energy cannot be created or destroyed; only transformed

  • living systems follow this law along w/other laws of energy

• energy is usually used frm the energy stored in chemical bonds

✦﹒living systems req. a exchange of matter

• atoms + molecules frm the environment r necessary to new new molecules, including—

  • carbon, used to build ALL macromolecules, store energy + form cells

    • its need of 4 bonds to complete its valence shell give it great versatility

  • nitrogen, used to build nucleic acids + proteins

  • phosphorus, used to build nucleic acids and certain lipids

﹙1.3 - Intro to Biological Macromolecules﹚

✦﹒monomers make polymers

• all macromolecules are polymers

• ALL monomers have carbon

• polymers are specific to the monomers they consist of

• monomers result from hydrolysis

  • this is where polymers are hydrolyzed (broken down) into monomers during the reaction

  hydrolysis reaction where maltose (polymer) with water from the environment breaks down into two glucose molecules (monomers)

• polymers result from dehydration synthesis

  • oxygen and two hydrogen molecules from the monomers will break off to form water and there the monomers will form a covalent bond together becoming a polymer

  • this reaction consumes energy

  reaction where two glucose molecules (monomers) form maltose (polymer) with the addition of water

﹙✦﹚﹒ my teacher said that dehydration synthesis “comes up a lot” so best if you understand this reaction :)

﹙Carbohydrates & Lipids﹚

✦﹒carbohydrates are composed of linear chains of sugar monomers connected by covalent bonds

• chains may be linear or branched

• small direction of change can change function

• made up of CH₂O in a 1:2:1 ratio

✦﹒saccharides are carbs that consist of sugar molecules

• monosaccharides r composed of one sugar tht provide a quick energy source

  • ex: ribose

  • monomer of carbohydrates

• disaccharides r double sugars composed of double sugars

  • ex: matrum, lactose

• polysaccharides r polymers composed of many sugars that are joined together by dehydration reactions

  • cellulose is a structural polysach. that helps build strong exoskeletons within organisms

  • starch is a storage polysach. that stores energy; plants store this, while animals store glycogen

    • has a curved shape, easily broken down

✦﹒lipids is a nonpolar chain that mixes poorly w/water due to structure

• examples include the various fats (triglyceride, fatty acid)

  • they r large molecules assembled by smaller molecules via dehydration reactions

  • fatty acids work as long-term energy storage

    • can be saturated, which turns solid at room temp.

    • can be unsaturated

• another example includes phospholipids

  • has 2 fatty acids instead of 3

  • in water, forms a bilayer to shield the tails frm water

﹙Proteins﹚

✦﹒proteins are made up of amino acids

• amino acids have directionality with an amino terminus/group and carboxyl terminus/group

  • amino acids r added to the carboxyl grp of a growing peptide chain by formation of covalent bonds

• amino acids are connected together by peptide bonds

  • together, amino acids form a polypeptide chain (polymer of amino acids)

• the r-group of the amino acid is the only thing that differs btwn each amino acid; its how each amino acid is different from each other

  common structure of amino acids

✦﹒proteins have different levels of structures

• primary structure is a linear chain sequence of amino acids held together by peptide bonds

  • the last thing remaining when a protein denatures

• secondary structure is created btwn the carboxyl grp and amino grp

  • can fold as a alpha helix shape or beta pleated sheet

    

    • formed frm the product of primary structure

    • stabilized by hydrogen bonds of primary structure

• tertiary structure is the overall 3D shape of the protein composed of many interactions btwn the side chains/groups of various amino acids; these bonds stabilize the protein

  • amino acids may have a charge— negative and positive charges will bond together and create an ionic bond on the protein

  • hydrogen bonds will form between polar r groups

  • disulfide bridge will be formed between two cysteine amino acids

  • hydrophobic interactions occur when nonpolaramino acids fold inwardsto hide itself from water (nonpolar = hydrophobic)

  • hydrophilic interactions occur when polaramino acids fold outwardstowards the water (polar = hydrophilic)

• quaternary structure is the overall protein structure that is frm aggregation of polypeptide subunits

╭ Other Resources :

:: amoeba sisters ﹒﹒ video on protein structure and folding

﹙✦﹚﹒the structures of protein is very important to understand, especially what happens if one fails

﹙Nucleic Acids﹚

✦﹒r polymers (can be DNA or RNA)made up of monomers called nucleotides

• a nitrogenous base is classified as a

  • pyrimidine (uranine [RNA only], cytosine, thymine), consisting of a six-membered ring of carbon and nitrogen

  • purine (adenine, guanine) , consisting of a six-membered ring fused w/a five-membered ring

╭ Other Resources :

:: amoeba sisters ﹒﹒ a video on ALL the biomolecules (carbs, lipids, proteins, nucleic acids)