Unit 1 Vocabulary

Null hypothesis

a fundamental statistical assumption that there is no significant difference, relationship, or effect between variables or groups

Covalent Bonds

a chemical bond where atoms share on or more pairs of electrons, forming during the process of dehydration synthesis

Polar Covalent Bonds

electrons are shared unequally.

ex. water

Nonpolar Covalent Bonds

electrons are shared equally between atoms

ex. methane

Ionic Bonds

one atom transfers an electron to another atom

ex. protein and nucleic acids

Hydrogen Bonds

a weak chemical bond formed with a slightly positive hydrogen atom and a slightly negative atom. These bonds bind water molecules together, and form the double helix seen in DNA

Isotopes

a version of a chemical element that has the same number of protons but a different number of neutrons in its nucleus

Water properties

cohesion, adhesion, high surface tension, high surface heat, capillary system, expansion when cooling

Cohesion

water molecules are attracted to each other, causing them to stick together

Adhesion

polar nature of water and the resulting hydrogen bonds causes water to stick to other surfaces or substances, except, however, nonpolar/waxy surfaces

Capillary Action

the ability of a liquid to flow in narrow spaces without external assistance, often moving against the force of gravity. Adhesion and Cohesion work together here

ex. xylem in plants

water expansion

when frozen, water molecules space apart in a rigid crystalline structure that floats on top of the water as it is less dense

Carbohydrates

organic macromolecules composed of carbon, hydrogen, and oxygen in an approximate 1:2:1 ratio, providing short term energy through glucose, storage through starch/glycogen, and structural support for plants through cellulose.

Protein

organic macromolecules composed of carbon, hydrogen, oxygen, and sometimes sulfur. Consisting of one or more chains of amino acids, protein help speed of chemical reactions through enzymes, provide structure through keratin, transport substances across membranes through protein channels, act as chemical messengers through hormones, defend the body against disease through antibodies, help in contracting muscles, and store long term energy.

Enzymes

biological catalysts that increase the rate of chemical reactions by lowering the activation

Hormones

chemical messengers that are secreted into the bloodstream or other bodily fluids to target specific cells, tissues, or organs to regulate physiology, development, and homeostasis

Lipid

organic marcromolecules composed of carbon, hydrogen, oxygen, and sometimes phosphorus. This diverse group of nonpolar, hydrophobic organic molecules make up fats used for insulation, phospholipids that make up the phospholipid bilayer, and steroids used for signaling and communication. The two types include saturated, made of straight chains only single C-C bonds, and unsaturated, made up of bent chains and one or more C=C double bonds

Phospholipids

a type of fat that makes up the phospholipid bilayer, being the main component of the cell membrane. Phospholipids consist of a hydrophilic head and a hydrophobic tail, aking the membrane semi-permeable

Nucleic Acid

organic macromolecules composed of carbon, hydrogen, oxygen, nitrogen, and phosphorus. These biological molecules help store, transmit, and express heredity information through DNA and RNA

Dehydration Synthesis

the process of building macromolecules by removing H2O. This is an anabolic/endergonic process, as it requires an input of energy

Hydrolysis

the process of breaking down macromolecules by adding H2O. This is a catabolic/exergonic process, as it releases energy

Pyrimidines

single ringed structures, which include cytosine, thymine, and uracil

Purines

double ringed structures which include adenine and guanine