Ap Bio Summer Work Test

Element

• one of 118 unique substances that cannot be broken down into smaller substances

• each element has unique properties and a specific number of protons

Compounds

• a substance composed of molecules consisting of atoms of at least two different elements

• chemically bonded

Mixtures

• a physical combination of two or more pure substances

• homogeneous: uniform composition

• heterogenous: not uniform composition

Protons

• +1 charge

• 1 amu mass

• found in the nucleus

Neutrons

• 0 charge

• 1 amu mass

• found in the nucleus

Electrons

• -1 charge

• 0 amu

• found around the nucleus

Ionic Bonding

• between a cation and an anion

• anions are negative ions formed by gaining electrons

• cations are positive ions formed by losing electrons

• electron transfer occurs to fill the outermost shell of an atom and make them more stable

  • some atoms are more stable when they gain or lose an electron(s) and form ions

Covalent Bonding

• between two atoms

• the more covalent bonds between two atoms, the stronger their connection

• more common than ionic bonds in the molecules of living organisms

• electrons are shared between the two elements to fill the outermost shell of each, making both elements more stable

• polar covalent: unequal sharing

• nonpolar covalent: equal sharing

Organic Compounds

• carbon-based molecules

• bonded with hydrogen, sulfur, oxygen, nitrogen, or phosphorous

• carbon atom has unique properties that allow it to form covalent bonds to as many as four atoms

Functional Groups

• groups that occur within molecules and confer specific chemical properties to those molecules

• found along the carbon backbone of macromolecules

• 7 groups

  • hydroxyl

  • sulfhydryl

  • methyl

  • carboxyl

  • carbonyl

  • amino

  • phosphate

Hydroxyl

• -OH

• polar

Sulfhydryl

• -SH

• polar

Methyl

• -CH₃

• nonpolar

Carboxyl

• -COOH

• charged, ionizes to release H⁺

• considered acidic because it releases H⁺ into solution

Carbonyl

• >CO

• polar

Amino

• -NH₂

• charged, accepts H⁺ to form NH₃⁺

• considered basic because it removes H⁺ from solution

Phosphate

• -OPO₄H₂

• charged, ionizes to release H⁺

• considered acidic because it can release H⁺ into solution

Structure of water

• polar

• contains hydrogen and polar covalent bonds

Water’s polarity

• composed of polar molecules

• oxygen is more electronegative than hydrogen, so oxygen generates a partial negative charge and hydrogen generates a negative charge

• each water molecule attracts other water molecules because of the opposite charges, forming h bonds

Water Cohesion

• water molecules are attracted to each other

• allows water to stay above a slightly overfilled glass

• surface tension

Water Adhesion

• the attraction between water molecules and other molecules

• sometimes stronger than cohesion

• allows water to “climb” up the tube placed in a glass of water

• water moves up roots/stems due to adhesion

Water Density

• Solid water (ice) has a lower density than its liquid form due to the way hydrogen bonds are oriented when it freezes

• water molecules form a crystalline structure maintained by hydrogen bonding when water freezes

Water Solvency

• water has slightly positive and negative poles that allow ions and polar molecules to dissolve in it

• solvent: a substance capable of dissolving other polar molecules and ionic compounds

Water Latent Heat of Vaporization

• the amount of energy required to change one gram of a liquid substance into a gas

  • 586 cal is required for water

• water is heated to boiling point and h bonds are broken, allowing molecules to escape as gas

Water Specific Heat Capacity

• property caused by h bonding among water molecules

• the amount of heat one gram of a substance must absorb or lose to change temp by one degree celsius

  • 1 cal for water

• water has the highest spc of any liquid

Carbohydrates

Elements (CHO)

• carbon

• hydrogen

• oxygen

Monosaccharides

• simple sugars

• number of carbons usually ranges from 3-7

• include glucose, galactose, and fructose

  • all 3 are isometric monosaccharides, meaning they have the same formula but different structures

  • C₆H₁₂O₆

Function

• provide energy for the cell

• provide structural support to plants, fungi, and arthopods

Monomers

• single, small molecular unit

Polymers

• large molecule made up of multiple monomers

Disaccharides

• form when two monosaccharides undergo a dehydration reaction

• sucrose=glucose+fructose

• lactose=glucose+galactose

• maltose=glucose+glucose

Dehydration Synthesis

• a chemical reaction in which a molecule of water is removed between two linking monomers

Hydrolysis

• polymers are broken down into monomers'

• a reaction in which a water molecule is used during breakdown of another compound

Polysaccharides

• a long chain of monosaccharides linked by glycosidic bonds

  • amylopectin

  • amylose

  • cellulose

  • glycogen

Lipids

Elements (CHO)

• carbon

• hydrogen

• oxygen

Fatty Acids

• a long chain of hydrocarbons to which a carboxyl group is attached

• saturated

  • there are only single bonds between neighboring carbons in the hydrocarbon chain

  • the number of hydrogen atoms attached to the carbon skeleton is maximized

• unsaturated

  • hydrocarbon chain contains a double bond

Triglycerides

• formation

  • glycerol + 3 fatty acids → triglycerol + 3 water molecules (dehydration reaction)

• structure

  • 3 fatty acids attached to a glycerol by ester bonds

• function

  • long term energy storage

  • insulation

Phospholipids

• structure

  • hydrophilic head is made up of a phosphate and a glycerol

  • hydrophobic tails are made up of 2 fatty acids

• function

  • major constituents of the plasma membrane

  • responsible for the dynamic nature of it

Waxes

• cover the feathers of some aquatic birds and the leaf surfaces of some plants

• hydrophobic

• made up of long fatty acid chains esterified to long-chain alcohols

Steroids

• have a fused ring structure

  • do not resemble other lipids

• hydrophobic and insoluble in water

• all steroids have 4 linked carbon rings and several have a short tail

  • many also have the -OH functional group, putting them in the alcohol classification (sterols)

Cholesterol

• most common steroid

• mainly synthesized in the liver

• precursor to many steroid hormones

• component of the plasma membrane of animal cells

• LDL cholesterol

  • “bad” cholesterol

  • may lead to plaque deposition in the arteries, resulting in heart disease

• HDL cholesterol

  • “good” cholesterol

  • absorbs extra cholesterol in the blood and brings it back to the liver

Protein

Elements (CHON)

• carbon

• hydrogen

• oxygen

• nitrogen

Structure

• long chains of different sequences of the 20 amino acids that each contain an amino group (-NH₂), a carboxyl group, and a variable group

Formation of Dipeptides and Polypeptides

• two or more amino acids are joined in a dehydration reaction to form the de/polypeptide and a water molecule

Dipeptides

• polymer consisting of two amino acids

Polypeptide

• polymer consisting of multiple amino acids

Essential Amino Acids

• amino acids that are necessary for construction of proteins in the body although not produced by the body

• they are obtained from the diet

Primary Structure

• the unique sequence of amino acids in a polypeptide chain

• determined by the gene encoding protein

• a change to the sequence changed the function

Secondary Structure

• the local folding of the polypeptide in some regions

• most common are the a-helix and the b-pleated sheet

• held together by hydrogen bonds

  • a-helix: h bonds form between one amino acid and another amino acid that is four amino acids along the chain

  • b-pleated sheet: h bonds form between atoms on the backbone of the polypeptide chain to create the pleats

• found in the most globular, fibrous proteins

Tertiary Structure

• the unique 3D structure of a polypeptide

  • the interactions among the R groups creates this structure

• nature of R groups counteract the formation of the h bonds

Quaternary Structure

• some proteins are formed from several polypeptides, also known as subunits

• weak interactions between subunits help to stabilize the overall structure

Functions of Proteins

• digestive enzymes: help in digestion of food by catabolizing nutrients into monomeric units

• contractile proteins: effect muscle contraction

• transport proteins: carry substances in the blood or lymph throughout the body

• defense proteins: protect the body from foreign pathogens

• hormone proteins: coordinate the activity of different body systems

• structural proteins: construct different structures, like the cytoskeleton

• storage proteins: provide nourishment in early development of the embryo and the seedling

Nucleic Acids

Elements (CHONP)

• carbon

• hydrogen

• oxygen

• phosphorus

Function

• most important macromolecules for the continuity of life

• carry the genetic blueprint of a cell and carry instructions for the functioning of a cell

Two Types

• deoxyribonucleic acid (DNA)

  • genetic material found in all living organisms

• ribonucleic acid (RNA)

  • involved in protein synthesis

• their monomers are: nucleotides

Nucleotide Structure'

• phosphate group

• pentose sugar

  • contains 1 H and 1 OH in DNA (deoxyribose)

  • contains 2 OH in RNA (ribose)

• nitrogenous base

Nitrogenous Bases/Rules

• adenine and guanine are classified as purines (pure as gold)

  • two carbon-nitrogen rings

• cytosine, thymine, and uracil are classified as pyrimidines (cut the py)

  • single carbon-nitrogen ring

• only certain types of base pairing are allowed

  • A can pair with T (apple in the tree)

  • G can pair with C (car in the garage)

• DNA strands are complementary to each other

DNA

• found in the nucleus of eukaryotes

• structure

  • double helix

  • the sugar and phosphate are on the outside of the helix, forming the backbone of the DNA

  • the nitrogenous bases are stacked in the interior, in pairs bound together by hydrogen bonds

  • the two strands of the helix run in opposite directions

• functions

  • controls all of the cellular activities by turning on and off genes

RNA

• structure

  • single stranded

  • made up of ribonucleotides that are linked by phosphodiester bonds

    • uses uracil instead of thymine

• functions

  • mainly involved in the process of protein synthesis

• types of RNA molecules

  • transfer RNA (tRNA)

  • messenger RNA (mRNA)

  • ribosomal RNA (rRNA)