L2. Chemical components of a cell Flashcards
what are the four types of macromolecules
- polysaccharides, glycogen, and starch (in plants)
- fats and membrane lipids
- proteins
- nucleic acids
macromolecules - polysaccharides, glycogen, and starch (in plants)
made up of sugars
macromolecules - fats and membrane lipids
made of fatty acids
macromolecules - proteins
made of amino acids
macromolecules - nucleic acids
made of nucleotides
define nucleotides
the building blocks of nucleic acids (DNA, RNA)
nucleotides - explain their functions
- genetic code (DNA, RNA)
- energy carriers
- co-enzymes
- cell signaling
nucleotides: genetic code - difference between DNA and RNA
- DNA: Deoxyribonucleic Acid, missing one hydroxyl group in 2 position
- RNA: Ribonucleic Acid, hydroxyl group in 2 position
nucleotides: genetic code - similarities between DNA and RNA
- Sugar backbone
- Nitrogenous base
- Phosphates
- phosphodiester bonds
- Synthesis always happens 5’ → 3’
- Base pairing of complementary strand creates the protein
- 1 start codon and 3 stop codon
nucleotides: genetic code - Phosphates
- they are hydrolyzed by the hydroxyl group
- this gives energy to drive the growing RNA or DNA strand
nucleotides: genetic code - phosphodiester bonds
- how nucleotides are joined together
- the bonds are between 5’ and 3’ carbon atoms on the sugar via a phosphate group
nucleotides: genetic code - why must synthesis happen from 5’ -> 3’
- 3’ hydroxyl is important for creating phosphodiester bond
- Without it, you cannot add a growing nucleotide
nucleotides: genetic code - explain the functions of RNA
- transcribe the genetic code
- translate the genetic code: tRNA
- structural - ribosomal RNA
nucleotides - energy carriers
- nucleotides carry chemical energy in their easily hydrolyzed phosphoanhydride bonds
- when you break the phosphoanhyride bonds, it creates a lot of energy and enzymes can use the energy to create work
- Ex: ATP
nucleotides: energy carriers - ATP
- it is a phosphorylated nucleotide
- consists of a ribose sugar
- consists of a hydroxyl group
- it is a ribonucleotide
- serves as the energy currency of the cell
nucleotides: energy carriers - what makes dATP different than ATP
- it is a nucleotide used to synthesize DNA
- consists of a deoxyribose sugar
- consists of a hydrogen
- it is a deoxyribonucleotide
- serves as a precursor for DNA synthesis
nucleotides - coenzymes
- nucleotides can combine with enzymes to form coenzymes
- they usher reactions
- ex: coenzyme A (CoA)
nucleotide: coenzymes - CoA
Nucleotide derivative that is used to facilitate catabolic reactions
nucleotide - signaling
- nucleotides can be used as signaling molecules in the cell
- cyclic AMP: facilitates signals more quickly
nucleotides - how do different cells express different genes
- each cell have a specific coordinated expression of genes that need to be turned on
- resulting in different cells having different genes turned on and expressed
amino acids - explain the general formula
- R side chain
- amino group
- alpha-carbon atom
- carboxyl group
- it is read from N-C terminus
amino acids - R side chain
- it is what makes each amino acid unique
- each R group is different and the order in a particular sequence of a protein will determine the protein’s function
amino acids - explain their cellular roles
- protein synthesis
- neurotransmitters (GABA, Glutamate)
- precursors to other molecules
- metabolites (serotonin, melatonin)
amino acids - making proteins
- DNA is transcribed into mRNA
- mRNA is translated into amino acids
- each codon (3 base pairs) corresponds to one amino acid
- amino acids form polypeptide chains
- polypeptide chains fold into proteins
amino acids: making proteins - peptide bonds
- they are formed when two proteins have combined
- a water molecule is kicked off when the bond is formed
- the peptide bond is stiff and is formed around the C-N bond
amino acids: making proteins - tripeptide
these are non-peptide bonds that are flexible rather than stiff
amino acids - what are the essential amino acids
- they are 11
- we get it from food
amino acids - what are the non-essential amino acids
- they are 9
- our bodies can produce it
carbohydrates - what are monosaccharides
- simple sugars
- formula: (CH2O)n
- n = 3, 4, 5, or 6
- ex: glucose or ribose
carbohydrates - what are disaccharides
sucrose = glucose + frutose
carbohydrates - what are olygosaccharides
2-10 monomers
carbohydrates - what are polysaccharides
100s - 1000s subunits
carbohydrates - explain the cellular roles
- energy source
- mechanical source (cellulose, chitin)
- glycoproteins and glycolipids have many functions
carbohydrates: cellular roles - energy source
- quick use (glucose)
- long term storage (glycogen, starch)
carbohydrates: cellular roles - glycoproteins and glycolipids
- intracellular signaling
- cell surface receptor interactions
- adhesion
- protein interactions
carbohydrates - explain glycosidic bonds
- these bonds make disaccharides
- can be formed through condensation (water expelled) or hydrolysis (water consumed)
- a proteins function can be determined based on how a protein is glycosylated (via adding vs losing a sugar)
carbohydrates: energy storage - starch
- simple polysaccharide
- plant cells
- polymer and long-term storage of glucose
carbohydrates: energy storage - what is glucose
an energy source and reserve for cells
carbohydrates: energy storage - what is glycogen
- in animal cells
- polymer and long-term store of glucose
- as its sugars get broken down, the sugars are fed into the mitochondria to make ATP
carbohydrates: mechanical support - what is cellulose
- in plant cells, within the cell wall
- polymer of glucose
- linear
carbohydrates: mechanical support - what is chitin
- in insect exoskeleton and fungal cell wall
- linear polymer of GlcNAc, which is a derivative of glucose
carbohydrates - what are complex oligosaccharides
- these are linked to proteins or lipids
- they are proteins that have a sugar sequence that is non-repetitive
- this can then change the function of the protein
- can facilitate new interactions between proteins
lipids and phospholipids
- make up cell membranes
- ex: fatty acids
lipids and phospholipids - fatty acids
- behaves as an acid
- reactive
- covalent linkage to other molecules
- hydrophilic carboxylic acid head (outside the head)
- hydrophobic hydrocarbon tail (inside cell)
- whole molecule is called amphipathic
lipids and phospholipids - saturated vs unsaturated fatty acids
- saturated: all spaces are filled with hydrogen and makes the membrane more stiff
- unsaturated: some spaces are not filled with hydrogen, this then forms double bonds creating a kink. This makes to membrane more flexible
lipids and phospholipids - lipid aggregates
- lipid aggregates form a bubble in contact with water due to their amphipathic properties
- when washing your hands, the soap forms aggregates and the germs fall on the outside of the aggregate. This then allows them to be washed off with water
lipids and phospholipids - what are phospholipids
- they have a hydrophilic head (outside cell) and a hydrophobic fatty acid tail (inside cell)
- this forms the lipid bilayer
lipids and phospholipids - glycolipids
- they are lipids with a sugar head group
- important for: membrane stability, cell-cell interactions, anchor for proteins, and cell signal transduction
lipids and phospholipids - triacylglycerols
- they form large spherical fat droplets in the cell cytoplasm
- they are insoluble in water but soluble in fat and organic solvents
- they serve as concentrated food reserves
lipids and phospholipids: triacylglycerols - where are they found
- in animals: fats
- in plants: oils
lipids and phospholipids - fatty acid derivatives
- composed of aromatic rings
- maintains membrane fluidity
- ex: steroids and hormones
lipids and phospholipids: fatty acid derivatives - steroids
- cholesterol
- prevents membranes from being too fluid as temperature gets too hot
