Exam 2 Flashcards
Polymer
A long molecule consisting of many similar building blocks called monomers.
What are the classes of life’s macromolecules?
-carbohydrates
-proteins
-nucleic acids
-lipids are not polymers but are large
How to build and break polymers?
Polymers are broken down by hydrolysis
Monomers are linked by dehydration
Proteins are made of what
Amino acid polymers, bonded by peptide bonds
Enzymes
The catalyst for hydrolysis needed to break apart polymers, especially proteins. “World’s tiniest and most specialized chemists”. They are structural proteins that make up hair and fingernails. Each enzyme is highly specialized for the specific molecule they break apart.
How many amino acids are there?
Only 20, but there are over 100k proteins that can be built
Carbohydrates, definition, structure and function
Include sugars and polymers of sugar (monosaccharides and disaccharides are sugars) (polysaccharides are complex carbs). Functions as energy storage and can have a structural role.
Structure of monosaccharides/carbs
CH2O. Most common is glucose. Monosaccharides are also known as simple sugars
Disaccharides
Formed when dehydration links two monosaccharides
Polysaccharides
Starch is a storage polysaccharide of plants, made entirely of glucose monomers and is used for energy. Cellulose is a major component of plant cell walls (aka fiber)
What has cell walls? And who is the exception?
Plants (made of cellulose), fungi and bacteria (made of peptidoglycan) have cell walls and cell membranes. Humans are the exception.
Lipids: Definition, function, structure
Largely hydrophobic (non polar) and include biologically important lipids such as fats, phospholipids and steroids. Functions as structure (phospholipids in cell membranes), long term energy storage (fats), hormones (steroids)
Phospholipids
Are both hydrophobic in the non polar tails and hydrophilic in the polar heads. They are significant since they form the phospholipid bilayer and prevent most “stuff” from leaking across itself.
Proteins: Definition, structure and function
They are polymers of amino acids comprised of an amino group, a side chain, and a carboxylic acid group. Functions include structural support, storage, transport, cellular communications, movement
Nucleic acids
Polymers of nucleotides. Held together by hydrogen bonds! The structure is a phosphate group, sugar group, and a nitrogenous base (A, T, C, G). There are 2 types: DNA or deoxyribonucleic acid which encodes the amino acid sequence of proteins, and RNA or ribonucleic acid which builds proteins. The double helix backbone is the sugar and phosphate groups, and the nitrogenous bases are the rungs.
The names of the four nitrogenous bases
A-adenine, T-Thymine, C-cytosine, G-guanine. A and T can only pair together and C and G can only pair together.
Prokaryotic cell structure
Cell wall
Cell membrane
Cytoplasm (aqueous interior of water etc)
Ribosomes (protein builders and technically not organelles since they aren’t membrane bound)
DNA (floating nucleotides)
Cell membrane
Phospholipid bilayer with embedded proteins that forms the boundary of cell walls. What functions do those proteins perform? Transport proteins, embedded with the tail outside, example is glucose
Ribosomes
Complexes of RNA and protein that carry out protein synthesis
Special features of plant cells
Chloroplasts
Water vacuole
Cellulose cell wall
What small non polar molecules freely cross the membrane with simple diffusion?
O2 and CO2, since they are both water soluble
Semipermeable membrane
A membrane that allows certain molecules or ions to pass through while restricting the movement of others. The selective permeability is dependent on size, charge, and solubility of the molecules or ions. Larger molecules, polar molecules (glucose), and charged ions may be restricted.
Diffusion
The movement of molecules from an area of higher concentration to an area of lower concentration