Chapter 2 - Chemical Composition Of The Body Flashcards
Physiological processes are based on __________ ___________, a general understanding of chemical principles is necessary.
chemical reactions
What is an element?
a substance that can’t be broken down into other substance by chemical means (ex. carbon cannot be broken down/converted into nitrogen)
How is an element related to an atom?
elements are made up of atoms. atoms are made up of subatomic particles (protons, neutrons, electrons)
Name the top 4 elements that make-up most of the body mass.
CHON
- carbon
- hydrogen
- oxygen
- nitrogen
What do you call substances that make up less than 0.01% of body mass?
trace elements (ex. iron, zinc, copper; metals)
Name the 4 elements that make up the least of body mass
CaP SCl
- Calcium
- Phosphorus
- Sodium
- Chloride
What is the smallest unit of an element that has all the chemical properties of that element?
atom (ex. carbon element is composed of several carbon atoms)
Name 3 subatomic particles and indicate whether there is a charge
proton (+), neutron, electron (-)
an atom is _________ which typically means that the number of ________ equals the number of ____________
neutral, protons, electrons
What areas of an atom can you find subatomic particles?
- nucleus (protons and neutrons)
- orbitals/electron shells (electrons)
What is at the center of an atom?
nucleus (protons and neutrons)
H has NO neutrons, only one proton
Compare atomic mass to the atomic numer
atomic mass: #p + #n
atomic number: #p
(may also equal #e in a NEUTRAL atom)
Orbitals or shells are ______ levels that surround the nucleus of an atom (electrons orbit the nucleus)
energy
If an atom has a neutral charge, what can you say about its number of subatomic particles?
the number of protons is equal to the number of electrons
If an unknown atom has 9 neutrons and 9 electrons total, what is its atomic number and atomic mass?
atomic number: 9
atomic mass: 18
How many electrons can be held in the first, second, and third orbital/shell.
1st shell: 2 electrons
2nd shell: 8 electrons
3rd shell: 18 electrons
The outermost shell is called the ________ _________. It contains _________ _________
valence shell
valence electrons
Atoms are most _______ when the _________ _______ is filled to maximum capacity
stable
valence shell
valence electrons in _______ outer shells participate in _______ _______
unfilled
chemical bonding
What are valence electrons
valence electrons are electrons found on the valence (outer) shell of an atom
If an unknown atom has 14 protons, how many electron shells are present surrounding the nucleus? How many valence electrons are present?
- 3 electrons shells
- 4 valence electrons
Define the Octet Rule. What can an atom do in order to satisfy the Octet rule?
- octet rule states that an atom requires 8 electrons in its outer shell in order to be stable/non-reactive state
- to satisfy the rule, atoms that do not have 8 valence electrons will gain, lose, or share electrons until they are surrounded by 8 valence electrons
What atoms are exceptions to the octet rule?
H (hydrogen) and He (helium) are stable with 2 valence electrons
What are compounds?
Name the two basic types of compounds
chemical structures with 2 or more atoms combines in a fixed ratio
(ex. H20, Na+Cl-, CH4)
- molecular compounds (covalent bonds)
- ionic compounds (ionic bonds)
How do you tell if an atom will become a molecule or an ion?
- atoms with 4,5,6 valence electrons share electrons (molecule)
- atoms with 1,2,3,7 valence electrons lose or gain electrons (ion)
If an atom has 7 electrons total, will it be a part of a molecule or ion? Explain.
molecule.
If an atom has 7 electrons total, that means the # of valence electrons must be 5.
atoms with 4,5,6, valence electrons will be part of a molecule compound/molecule
How do covalent bonds form?
covalent bonds are made by the sharing of electrons
a compound in which atoms are held to each other by covalent bonds is called a ______ _________
molecular compound
covalent bonds can exist as a ______, ________, or ________ bond.
single, double, triple
Compare polar vs. non-polar covalent bonds. Give an example of a molecule that is held together by each type of covalent bond
Polar covalent bonds is involved with unequal sharing of valence electrons between 2 atoms (H20)
non polar covalent bond is involved with equal sharing of valence electrons between 2 atoms (CH4)
What do electronegative elements do? Provide examples of an electronegative element.
polar covalent bonds form when an electronegative element is present in a molecule
electronegative elements attract electrons to itself
(ex. oxygen (O) & nitrogen (N))
In a “_____” molecule there is a “_______” charge; however, the net charge is still ______.
polar
partial
zero
Compare polar molecules and nonpolar molecules
polar molecules: polar covalent bonds; dissolve in water (hydrophilic); water soluble (ex. H20, NH3).
nonpolar molecules: nonpolar covalent bonds; don’t dissolve in water (hydrophobic); water insoluble (ex. CH4)
Explain why ions are charges
ions are charged because atoms either lose or gain electrons (they will have either extra protons or electrons, thus giving them a charge).
in an ionic bond, one atom _____ electrons to another so that both have ______ valence shells
gives
filled
Compare a cation to a anion.
- both are in ionic bonds
- cation: is the electron DONOR; becomes positively charges
- anion: is the electron RECEIVER; becomes negatively charged
How are ionic compounds formed?
the attraction between cations (+) and anions (-) that form ionic bonds
How are ionic bonds made?
bonds made by charge attractions
ex. (- indicated ionic bond)
Na+ - - - - - - - - - - - Cl-
most ionic compounds ______ (______ ______)with no reaction when dissolved in water
dissociate
come apart
What happens when an ionic compound dissociates/comes apart in water? What are ionic compounds typically known as?
- negative side (-) of water is attracted to the cation (+), and the positive side (+) of water is attracted to the anion (-)
- the water will form hydration spheres around the ions and keep them separated
- known as salts, acids (H+), and bases (Cl-)
What are hydrogen bonds?
What do hydrogen bonds form between?
- weak bonds formed between 2 polar molecules based on opposite charges attracting (not based on electron sharing)
- form between water molecules (electropositive H atoms and electronegative O atoms)
- amino acids on protein to produce 3D structure of protein
- two stands of DNA molecule
What type of bond holds two strands of the DNA molecule together?
hydrogen bonds
What are hydrocarbons?
What can you say about the amount of energy found in hydrocarbons?
- hydrocarbons are molecules that contain carbon and usually hydrogen; non-polar and hydrophobic
- high energy in bonds of hydrocarbons
Name the different functional groups
- hydroxl (OH): alcohol
- animo (NH2): (part of amino acids) proteins
- carboxyl (COOH): acid
Name the four main categories of organic compounds
- Carbohydrates
- Lipids
- Proteins
- Nucleic Acids
What are carbohydrates also known as?
How can you identify a carbohydrate?
- AKA sugars
- names end in -ose
Name the four main categories of carbohydrates
- monosaccharides
- disaccharides
- oligosaccharides
- polysaccharides
Describe monosaccharides.
Give 3 examples.
- simple sugars; one subunit
- high energy source
- ex. glucose, galactose, fructose
What are the building blocks for other carbohydrates?
monosaccharides
Describe the composition of disaccharides
Give 3 examples.
- 2 monosaccharides joined together by a covalent bond
ex. sucrose, maltose, lactose
What type of bond is involved with carbohydrates?
glycosidic bonds (covalent)
glucose + glucose = ?
maltose (disaccharide)
glucose + galactose = ?
lactose (disaccharide)
glucose + fructose = ?
sucrose (disaccharide)
glucose + _________ = maltose
glucose (monosaccharide)
What process is used to build carbohydrates, lipids, proteins, and nucleic acids?
Describe this process
dehydration synthesis
- forms covalent bonds by removing an H atom from one monosaccharide, and an OH groups is removed from another to form H20
Describe hydrolysis
breaks bonds between monosaccharides; adds water and splits the molecule
What process is being done here?
glucose + fructose -> sucrose + h20
dehydration synthesis
What process is being done here?
maltose + h20 <- glucose + glucose
dehydration synthesis
What process is being done here?
lactose + h20 -> glucose + galactose
hydrolysis
Describe an oligosaccharide
What is the function of it?
- linkage of 3-10 monosaccharides
- exists as glycoprotein/glycolipid
- functions as “cell surface markers”
(ex. ABO blood typing is based on glycolipids on the surface of RBC)
Describe the composition of polysaccharides
Give some functional examples of a polysaccharide
- linkage of 10+ monosaccharides (generally glucose)
- starch: sugar storage in plants
- glycogen: sugar storage in animals (in liver and skeletal muscle)
- cellulose: cell wall of plant; indigestible for humans
- chitin: cell wall of fungus
What are lipids also known as?
Are they hydrophobic or hydrophilic? Why?
fats
hydrophobic due to high hydrocarbon content
What are the four categories of lipids
- triglycerides
- phospholipids
- steroids
- prostaglandins
Describe the composition of triglycerides
- formed by linking 1 glycerol and 3 fatty acids
- has 3 covalent bonds; ester bonds
- includes fats (solids) and liquids (oil)
What is a glycerol?
What is a fatty acid?
- glycerol: 3-carbon alcohol
- fatty acid: long, nonpolar hydrocarbon chain with a carboxyl (-COOH) at one end
How are saturated fats made?
there are single bonds in the fatty acid chain
How are unsaturated fats made
there are double bonds in the fatty acid chain
Describe saturated fatty acids (# of h atoms/bonds, energy, what it forms)
give an example
- max # of H atoms in HC chain
- single bonds only
- more energy available = more energy bc there are more hydrocarbon bonds
- forms fats
ex: palmitic acid
Describe unsaturated fatty acids (# of h atoms/bonds, energy, what it forms)
give an example
- less # of H atoms in HC chain
- double bond
- less energy (not as many hydrocarbon bonds)
- liquids
ex. linolenic acid
Is this an example of a saturated/unsaturated fatty acid?
c - c - c - c - c = c -c -c -c -c -c
unsaturated fatty acid
Compare the difference between fat and oil (state, chain arrangement, sourced)
fat:
- solid
- saturated fatty acids
- saturated chains packed closely together
- animal sourced
oil:
- liquid
- unsaturated fatty acids
- unsaturated chains packed less closely together
- plant sourced
What are the two subcategories of unsaturated fatty acids?
Compare the two
cis fat
- found in nuts, fish, and corn oil
- healthy; keeps the heart healthy by increasing levels of good cholesterol
trans fat
- behaves as if it were saturated fat (solid at room temperature)
What is the composition of a phospholipid?
What type of molecule can this be classified as?
- phosphate group (polar)
- glycerol molecule (non-polar)
- 2 fatty acids tails/chains (non-polar)
- amphipathic molecule
Define an amphipathic molecule
is part polar and part non polar, which makes them hydrophilic and hydrophobic at the same time
What is the important function of a phospholipid?
- major component of cell membrane as a double layer; acts as phospholipid bilayer
Why does the phospholipid bilayer exists as a mirror of itself?
its an amphipathic molecule, so the hydrophilic heads points towards h20, while the hydrophobic tails points toward one another.
Describe the composition of a steroid?
Give an example
- lots of HC -> non polar -> hydrophobic
- 3 six-carbon rings fused to a one carbon rings, plus its functional group
- ex. cholesterol
Describe the composition of a prostaglandin
What are the functions?
- fatty acid with a cyclic (ring) hydrocarbon group
- have -COOH (carboxyl) as a functional group
- ovulation
- uterine contraction
- inflammatory reactions
- regulate blood vessel diameter
- blood clotting
What type of covalent bond is formed in proteins?
peptide bond
Describe the composition of a protein
- made up of amino acid chain
- 20 different amino acids in nature (human body synthesize 11)
Describe the “anatomy”/structure of an amino acid
- contains central carbon that is bound to:
- amino group (NH2, protein)
- carboxyl group (COOH, acid)
- Hydrogen
- functional R group (variable; can be polar or non polar)
Give some examples of proteins and their functions
structural proteins: support cells shape
enzymes: speed chemical reactions
antibodies: part of immune system response
receptors: cell signaling (receiving communication from other cells for regulation of cell activity).
carrier proteins: located across cell membrane to move things in an out of cell
What is the association between protein function and protein shape?
the shape of a protein will determine the difficulty of its functions
(ex. simple shape = simple function)
What are the four levels of protein shape/structure?
- primary (1°) structure
- secondary (2°) structure
- tertiary (3°) structure
- quaternary (4°) structure
Describe the composition of the primary protein structure
- based on amino acid sequence/chain
- linear pattern
- short chain of animo acids = peptide
- long chain of amino acids = polypeptide
What is a peptide bond? Where does the water come from in the formation of a peptide bond?
- peptide bonds are bonds used to link amino acids together in a protein
- when amino acids are joined, H is stripped from the amino end of the amino acid, and an OH is stripped from the carboxyl end of another amino acid -> forms H20
Describe the composition of secondary protein structure
- based on weak H bonds between nonadjacent amino acids (introduce bends/folds)
- results in alpha helix and beta pleated sheet
Describe the composition of tertiary protein structure
- lots more bends/folds
- formed between interaction between R groups of non-adjacent amino acids
four main types of R group interactions:
- ionic bonds
- H bonds
- Van der Waals forces (interaction between identical R groups)
- Disulfide bridges (formed between 2 nonadjacent sulfur-containing amino acids; S - S )
Describe the composition of quaternary protein structure
What are its function
- covalent joining of multiple tertiary/polypeptide chains/subunits
examples: hemoglobin in RBC (4 polypeptides), antibody (4 polypeptides), hormone insulin (2 polypeptides)
Describe what happens during denaturation. What are some examples of things that can cause denaturation?
Denaturation is the loss of protein shape/structure, resulting in the loss of protein function
ex. ph and temperature
Describe the composition of nucleic acids?
What type of bond is made between nucleic acids?
- composed of nucleotides (5 carbon sugar; pentose, phosphate group, nitrogenous base)
- linked by covalent bond, phosphodiester bond
What are nucleotides made of?
- five-carbon sugar (pentose sugar)
- phosphate group
- base containing N (nitrogenous base)
What are the different families for nitrogenous bases?
Which bases pair together?
purine family (2 ring structure): adenine, guanine
pyrimidine family (1 ring structure): cytosine, uracil, thymine
- A + T
- C + G
What are examples of nucleic acids? How are these examples formed
DNA: sequence of bases codes for amino acids to make a protein
- deoxyribose (sugar)
- phosphate group
- ATGC (nitrogenous base)
- double stranded/helix
RNA
- ribose (sugar)
- phosphate group
- ACGU
- single stranded
Which nitrogenous base is exclusively found in DNA only? RNA only?
DNA only: Thymine (T)
RNA only: Uracil (U)
What is the purpose of RNA?
What are the three types of RNA?
- RNA is used to assemble a protein in the cytoplasm
- messenger RNA (mRNA)
- transfer RNA (tRNA)
- ribosomal RNA (rRNA)
