Biology slides 2
Atom
Basic unit of matter
Essential elements for life
25 elements are eseential for life; C(carbon), H(hydrogen), N(nitrogen), O(oxygen), P(phosphorus), S(sulfur) are >97% of this.
Covalent bond
The sharing of a pair of valence electrons by two atoms.
Ionic bond
A bond formed through electrostatic attraction between oppositely charged ions.
Polar covalent bond
A covalent bond between two elements with different electronegativities, resulting in unequal sharing of electrons.
Non-polar covalent bonds
A covalent bond between two elements with similar or identical electronegativities, resulting in equal sharing of electrons.
Hydrogen bond
A weak bond between a hydrogen atom and an electronegative atom.
Hydrophilic
A molecule that interacts with water and is soluble in it, typically containing polar bonds.
Hydrophobic
A molecule that does not interact with water and is not soluble in it, typically containing non-polar bonds.
Amphipathic
A molecule that contains both polar and non-polar regions.
Cohesion
The property of water that allows it to stick to itself, creating surface tension.
Specific heat
The amount of heat required to change the temperature of a subtsnce; water has a high specific heat.
Evaporative cooling
The process where the surface of an object becomes cooler during evaporation.
Density of ice
Ice is less dense than liquid water, allowing it to float.
Organic chemistry
The chemistry of carbon and all living things.
Biomolecules
Molecules that are essential for life, primarily carbon-based.
Carbon versatility
Carbon can form 4 covalent bonds; strong, single, double, and triple bonds, and bond with many diverse elements.
Carbohydrates
Organic compounds used to provide energy for cells.
Triglycerides
A type of fat used to store energy in the body.
Proteins
Biomolecules used to make more proteins and energy.
Vitamins and minerals
Essential nutritens that must be consumed for proper body function.
Caloric needs
Need ~2000 calories per day, 4 cal/gram for carbs and proteins, 9 cal/gram for fats.
Fats
Lipids can store energy, form cell structures, and can be involved in signalling.
Vitamins and minerals
Are organic or inorganic molecules we need in small quantities.
Nucleic acids
Include DNA (and RNA) and transmit genetic information.
Essential fatty acids & amino acids
Building blocks we need in our diet to form more complex molecules.
Carbs
Sugars / carbohydrates.
Role of carbs
Fuel and structure.
Carbohydrate formula
Cn (H2O)n.
Simple carbohydrates
Monosaccharides provide immediate energy, disaccharides must be broken down first to provide energy.
Examples of Simple Carbs
Include glucose, fructose, sucrose, and lactose.
Complex carbohydrates
Polysaccharides are broken down by the body into simple sugars, which takes longer, delaying hunger.
Example of Complex Carbs
Include starch.
Fiber
Complex carbs that we can't digest (ex: cellulose), typically coming from plants.
Polysaccharide carbohydrates
All made up of monosaccharides and have the chemical formula (CH2O)n.
Glycogen
Storage of energy in animals, formed when we eat carbohydrates and broken down when our body needs energy.
Starch
How plants store their energy, made up of two types of polysaccharide: amylose & amylopectin.
Amylopectin
Branched gluocse, ~70% of starch.
Amylose
Unbranched glucose, more dense.
Cellulose
Best known example of a structural polysaccharide, a chain of glucose positioned to make long, strong cables.
Dietary fiber
Molecules that an organism cannot break down, so they pass through the digestive system.
Hydrophilic fiber
Brings water molecules with them, hydrating the digestive tract, making constipation less likely.
Monosaccharides
Simple sugars used for quick energy.
Polysaccharides
Carbohydrates that are used for stored energy or structure.
Protein functions
Include selective acceleration of chemical reactions, storage of amino acids, coordination of activities, movement, protection against disease, transport of substances, response to chemical stimuli, and support.
Amino acids
Building blocks of proteins, made up of an amino group, carboxyl group, and a variable side chain (R group).
Side chain (R group)
The variable part of an amino acid that determines its properties.
Hydrophobic side chains
About half of the amino acids have side chains that do not interact well with water.
Hydrophilic side chains
About half of the amino acids have side chains that interact well with water.
Essential amino acids
Amino acids that must be obtained through diet.
Peptide bonds
Chemical bonds that link amino acids together to form polypeptides.
Polypeptides
Chain of amino acids that make up proteins.
Primary structure
The unique sequence of amino acids in a protein.
Secondary structure
Coils and folds in the polypetide chain found in most proteins.
Tertiary structure
The overall 3D shape of a protein determined by interactions among side chains.
Quarternary structure
The structure formed when a functional protein consists of multiple polypeptide chains.
Protein folding
The process that determines the 3D structure of proteins, which is crucial for their function.
Denatured protein
A protein that loses its 3D structure due to conditions that interrupt its forces.
Renatured protein
A protein that has regained its 3D structure after being denatured.
Diseases related to protein folding
Includes Cystic Fibrosis, Alzheimers, Parkinsons, and Creutzfeldt-Jakob disease.
Unique sequential chains
Unique sequential chains of amino acids give unique structures.
Lipids
Not grouped by structure, but by common property; they're mostly carbon and hydrogen.
Saturated fats
Solid at room temperature, packs together, typically comes from animals.
Unsaturated fats
Liquid at room temperature, healthier, often from plants.
Trans fats
Unsaturated fats that look like saturated fats and which the body reacts poorly to.
Energy storage
Fats provide long-term storage of energy but too much damages our circulatory system.
Caloric content
Fats contain far more energy per g than carbs or proteins (4 vs. 9 cal/g)
Essential fatty acids
Some fatty acids however (omega-3 & omega-6) are essential, meaning you can only obtain them in your diet.
Cholesterol
Cholesterol disrupts membrane and too much is linked to heart disease.
Waxes
Special hydrophobic molecules often used to keep water away.
Phospholipids
Consist of two hydrophobic fatty acids and a hydrophilic 'polar head group' which includes phosphorous.
Phospholipid bilayer
Cell membranes are bilayers of phospholipids, providing an impermeable barrier.
DNA
Long-term information storage.
RNA
Short-term information storage.
Nucleotide structure
Made up of a 5-carbon sugar, phosphate group, and a nitrogenous base.
Nitrogenous bases
Includes pyrimidines and purines.
Base pairing
In DNA, Adenine bonds with Thymine, and Cytosine bonds with Guanine.
RNA pairing
RNA matches A with Uracil instead of T.
Polynucleotide
A nucleic acid made of nucleotides.