Biochem Flashcards
Two main types of nucleus acids and what they contain
DNA
- deoxyribonucleic acid
- contains the hereditary code
RNA
- ribonucleic acid
- For protein synthesis
Monomers that make up nucleic acids and subunits
Nucleotides
- five carbon sugar “pentose” either deoxyribose or ribose
- phosphate group
- one of the four nitrogenous bases
RNA structure
A single strand that folds on itself (Single strand of nucleotides)
- does not necessarily take the shape of a helix
DNA structure
- has a double helix shape
- two strands are hydrogen bonded together at the nitrogenous bases
- nitrogenous bases points towards the middle
what is DNA base-pairing? what type of bond do they have, and what are the backbones made of?
- complementary base-pairing of nitrogen bases of nucleotides
- certain bases “fit” together
- nitrogenous bases are not covalently bonded.
- They are paired through hydrogen bonding
- The back bones are made of sugars and phosphates as they are bonded by dehydration synthesis
DNA base-pairing
- Adenine + Thymine (DNA) or Uracil (RNA)
- Guanine + cytosine
ATP (adenosine triphosphate)
- does it’s job as a single nucleotide
- it is an energy carrying molecule (nucleic acid)
- ATP undergoes hydrolysis and energy is released
- produced by cellular respiration in the mitochondria
What are enzymes?
- protein catalysts
- speed up rate of chemical reactions without being used
- they speed up chemical reactions by lowering the activation energy for a chemical reaction to occur
What do enzymes usually end in?
“Ase” such as lactase
Enzyme cofactors
Vitamins and minerals
Vitamins
- organic compounds that serve as coenzymes
- help enzyme function
Minerals
- inorganic compounds needed by the body in small amounts
- essential components of certain structures
What would happen without enzymes in the body?
- Chemical reactions would proceed way too slowly to be of any use to cells
- therefore enzymes are necessary for life to be possible
How do enzymes work?
- enzymes act only on specific substrates (reactants) for specific reactions
- substrate fits in the enzymes active site in a “lock and key” arrangement
Induced fit model (see notes for diagram)
- enzyme changes shape around the substrate in the active site
- substrate fits well into active site, then enzyme is induced move
Enzyme + substrate name, and why it works
- enzyme-substrate complex
- it is an unstable state such that bonds can be broken and new ones form
- The results are reacted products and unchanged enzyme, meaning enzyme can be reused
Degradation and synthesis
Degradation is when the substrate is broken down into smaller products
Synthesis is when they are combined to produce a larger product
How does temperature affect enzyme activity?
- reaction rate increases as temperature rises
- at a certain point when temperature is too hot, the enzyme becomes denatured as protein begins folding, decreasing reaction rate
- this is because the lock and key arrangement is lost
- therefore there is an optimal temperature range
How does pH affect enzyme activity?
- there is an optimal pH (acidity) for each enzyme to make enzyme more effective
Inhibitors
- Molecules that attach to enzymes and reduce their ability to bind substrates
Competitive inhibitors
- attached to the enzymes active site, competing with the substrate
Non-competitive inhibitors
- bind elsewhere on the enzyme, changes the enzymes through the shape, therefore rendering the active site less affective
Feedback inhibition
- product of an enzymes rxn acts as an inhibitor for the enzyme
Types of enzymes
- carbohydrases (amylase, Maltase, sucrase, lactase)
- lipases
- proteases (trypsin, pepsin, peptidases)
- nucleases, nucleosidases
Factors affecting enzymatic speed (6)
- substrate concentration
- temperature
- PH
- enzyme activation
- enzyme inhibition
- enzyme cofactors
How does substrate concentration affect enzyme activity?
- There are more collisions between substrate and enzyme
- maximum rate is achieved when all active sites of an enzyme or filled continuously with substrate
What is feedback inhibition?
- occurs when an enzyme cannot bind its substrate
- activity of cell enzymes is regulated by feedback inhibition
- poisons are enzyme inhibitors
How do enzymes break down carbohydrates?
- Broken down by amylases (salivary, pancreatic) to disaccharides (maltose, sucrose,lactose)
- The disaccharides are broken down by carbohydrases (maltase, sucrase, lactase)
- Result is monosaccharides aka simple sugar (glucose, fructoseX galactose)
How do enzymes break down fats?
- Fats (triglyceride) are broken down by lipase (pancreatic)
Result is glycerol and three fatty acids, aka your monomers
How do enzymes break down nucleic acids?
- Nucleic acids (DNA, RNA) are broken down by nucleases
Result is DNA or RNA nucleotides (monomer) - Nucleotides is broken down by nucleosidases into phosphate group, pentose, and nitrogenous bases
How do enzymes break down functional proteins?
- Broken down by gastric protease (pepsin)
Result is polypeptides (long chains of amino acids) - Broken down by pancreatic protease (trypsin)
Result is peptides (short chains of A.A) - Broken down by peptidases
Result is amino acid, aka monomer
