bio test 1 Flashcards
what is water made up of
2 hydrogen atoms and 1 oxygen atom
what kind of bond holds water together
covalent bond
how does a covalent bond form
it forms between atoms when each atom shares electrons
how are electrons shared in a water molecule
one electron from oxygen atom and one from hydrogen atom is shared to make a covalent bond; the electron pair is thus shared by both oxygen and hydrogen. However, the sharing is not equal. Oxygen atom is more electronegative. It attracts electrons towards itself more than hydrogen.
what are electrons
negatively charged ‘particles’ ( 1 electron = 1 negative charge)
is oxygen slightly negative or positive
slightly negative (delta negative)
is hydrogen slightly negative or positive
slightly positive (delta positive)
what does the slightly negative oxygen and slightly positive hydrogen result in
a molecule with slightly negative and positive poles (ends)
is a water molecule polar
yuh
dissolving and water
water can dissolve many things to a great extent and others to a lesser one or slightly lesser one. for this reason, water is known as a universal solvent.
does water dissolve other polar or ionic substances to a large extent
yuh
the slightly negative (delta negative ) ___ is attracted to the slightly positive (delta positive) ___ between neighbouring water molecules
oxygen, hydrogen
due to an attraction between hydrogen of one water molecule and oxygen of another, the water molecules are held together by a weak bond called ___
hydrogen bond/hydrogen bonding
properties of water:
1) Water molecules are cohesive and adhesive which makes it a lubricant
2) Water molecules are polar which makes it a good solvent
3) Water has a high heat capacity and high heat of vaporization which makes it a good temperature regulator
cohesive
refers to water molecules being able to stick/stay together
adhesive
refers to water molecules being able to stick to other surfaces
examples of water as a lubricant in our bodies:
1) lubricant in bone joints
2) lubricant in mucus and saliva
3) lubricant in digestive juices
4) lubricant in semen
does water have a high heat capacity and high heat of vaporization?
yuh
water is able to retain large amounts of ___
heat
does water have a high heat of vaporization?
yes. water is able to absorb large amounts of heat before it begins to evaporate
2 examples of water as a temperature regulator:
1) Normal human body temperature = 37 degrees Celsius; biochemical reactions in our body occur best at 37 degrees Celsius. when the body temp falls below normal, water retains. when the body temp rises above normal, water releases excess heat and the normal temp is maintained.
2) When it gets cold, shivering is another mechanism through which water in blood is able to retain heat to maintain normal body temperature.
acids and example of one in our bodies
compounds which produce hydrogen ions when dissolved in water.
ex: HCl produced in stomach
bases and example of one in our bodies
compounds which produce hydroxide ions when dissolved in water.
ex: HCO3- (bicarbonate ion). NaHCO3 is a salt which dissociates into sodium ion and bicarbonate ion.
pH
a measure of how many hydrogen ions there are in a given solution
when pH = 7, the solution is ___
neutral. the solution has equal amounts of hydrogen and hydroxide ions
when pH is greater than 7, the solution is ___
alkaline/basic. the solution has less hydrogen ions compared to OH- ions
when pH is less than 7, the solution is ___
acidic. the solution has more hydrogen ions compared to OH- ions
human blood has a slightly basic pH of ___
7.34 to 7.40
do pH and hydrogen vary opposite to each other?
yes. when the concentration of hydrogen ions increases the pH decreases so it becomes more acidic.
low pH indicates ____ while high pH indicates ___
an acidic solution, a basic solution
when the hydrogen concentration is up, the pH is down and ___
when the hydrogen concentration is down, the ph is up and ___
the solution becomes more acidic
the solution becomes more basic/alkaline.
significance of pH and 3 examples
biochemical reactions in our bodies occur best at optimum pH; the wrong pH will result in no reaction or process.
ex: 1) Saliva in mouth contains a starch digestive enzyme,
‘salivary amylase’, works best at 7 pH
2) Stomach produces a protein digestive enzyme, ‘pepsin’, works best at 2-3 pH.
3)Pancreas and small intestine produce digestive enzymes, work best at 8-9 pH.
explain biological buffers
Each biochemical has its own optimum pH. Buffers are the substances which help maintain pH in a narrow range.
explain 3 examples of biological buffers in the body:
1) Hemoglobin (Hb): pigment in our red blood cells (RBC) maintains constant blood pH of 7.34-7.40. pH of blood drops below normal= excessive hydrogen ions. Blood buffer removes extra hydrogen ions by binding with them. blood pH rises above normal= not enough hydrogen ions. Hemoglobin releases H+ ions as needed.
Hb + H+ ↔HHb 2) Bicarbonate ions, HCO3- , and the breathing system also helps maintain constant pH. HCO3- + H+ ↔ H2CO3 3) Bone buffer system helps maintain pH
monomer
mono = 1
refers to the building blocks/unit molecules
polymer
poly = many
refers to macromolecules/larger molecules made by putting together monomers/unit molecules/building blocks
examples of monomers and the polymers they can turn into
- glucose/monosaccharides => starch, glycogen, cellulose (polysaccharides)
- amino acids => proteins/polypeptides
- nucleotides => nucleic acids
- 3 fatty acids + glycerol => triglycerides/neutral fat/lipid
- 2 fatty acids + phosphate + glycerol => phospholipids
dehydration/condensation synthesis
- refers to the making of a polymer from its monomers
- the “OH” of one monomer and the “H” of another monomer join to make a molecule of water
- when water is removed, the 2 monomers join to make a polymer
2 examples of dehydration synthesis
- protein synthesis (recognize the diagram)
- excess blood glucose (monomer) is converted into glycogen (polymer) in the liver with the help of the hormone insulin produced by the pancreas. glycogen is stored in the liver.
hydrolysis
- refers to breaking apart a polymer into its monomers with the help of water
- water is added in the process of hydrolysis
example of hydrolysis
- our digestive system breaks down the polymers we consume into their monomers with the help of digestive enzymes
- the monomers are small enough to enter the blood. di or poly cannot enter the blood because they are too big to enter blood capillaries
many monomers produced by the digestive system first enter the ___ where they are reprocessed and used as needed
liver