Biology 140 Exam 1

cells

cells

the smallest units of life

metabolism

all of the chemical reactions that occur within the cells of living things

homeostasis

the relatively constant and self-correcting internal environment of a living organism

adaptive traits

all organisms have these traits which help them survive and reproduce in their natural environment

atom

a unit of matter that cannot be broken down by ordinary chemical means

tissue

a group of similar cells that perform the same function

organ

a structure with two or more tissues working together to perform the same function

organ system

at least two organs working together to perform a function

organism

an individual living thing

population

all individuals of the same species living in a distinct geographic area

community

all individuals of any species living together in a geographic area, they can potentially interact with each other

ecosystem

a community and its physical environment

biosphere

the part of Earth where life exists

science

an approach to answering questions through systematic documentation and experimentation

scientific method

a series of steps used to gather information and reach conclusions. the first step is making careful observations and asking questions.

hypothesis

a testable prediction/educated guess/answer to a question

controlled experiment

An experiment in which one variable is tested using two groups. One group is a the control group, while the other is the experimental group.

independent variable

the one variable that is manipulated in a controlled experiment

bacteria

a domain including unicellular prokaryotic organisms that do not tend to live in extreme environments

archaea

a domain including unicellular prokaryotic organisms that tend to live in extreme environments

eukarya

a domain including eukaryotic organisms whose cell(s) contain a membrane-bound nucleus and organelles

kingdoms

domain eukarya is split up into four of these (protists, fungi, plants, and animals)

inductive reasoning

reasoning that involves the accumulation of facts to form a conclusion or hypothesis

deductive reasoning

reasoning that involves making a hypothesis and then drawing more specific conclusions from it

placebo

a substance made to look like the drug being tested, but that has no effect (sugar-pill)

double-blind study

this occurs which neither researchers nor participants know which group is receiving treatment

matter

anything that takes up space and has mass

element

a pure form of matter containing only one kind of atom

isotopes

atoms that have the same number of protons but differ in the number of neutrons

radioisotopes

unstable, radiation-emitting isotopes which can be dangerous and/or useful, depending on context

compound

two or more elements that are chemically combined

covalent bond

a chemical bond that forms when two or more atoms share electrons in their outer shells

molecule

a chemical structure consisting of at least two atoms held together by covalent bonds

ion

an atom or group of atoms that carries either a positive or negative electrical charge

ionic bond

a chemical bond formed when one or more electrons are transferred from one atom to another. the resulting attraction is due to oppositely charged ions (one positive and one negative)

hydrogen bond

the attraction between a slightly positively charged hydrogen atom of one water molecule and a slightly negatively charged oxygen atom of another water molecule

acid

anything that releases hydrogen ions (H+) when placed in water (result=pH less than 7)

base

anything that releases hydroxide ions (OH-) when placed in water (result=pH greater than 7)

pH

a measure of hydrogen ion concentration in a solution

buffers

substances that prevent pH values from changing dramatically

macromolecules

large organic molecules found in living things

polymers

chains of monomers

monomers

building blocks of polymers

carbohydrates

sugars and starches that provide fuel for the body. the polymers of monosaccharide monomers

oligosaccharides

chains of a few monosaccharides joined together by dehydration synthesis

polysaccharide

a complex carbohydrate that forms when monosaccharides join together in long chains

lipids

compounds, such as fats, that do not dissolve in water

triglycerides

polymers made of three fatty acids bonded to glycerol. examples are fats and oils

saturated fatty acid

fatty acid with only single bonds linking the carbons in its tail. known as the less healthy fatty acid

unsaturated fatty acid

fatty acid with one or more double bonds linking the carbons in its tail. known as the healthier fatty acid

phospholipid

molecule that forms a bilayer in cell membranes, consists of a hydrophilic head and hydrophobic tail

protein

a polymer made of monomers called amino acids

amino acids

building blocks (monomers) of proteins

peptide

short chain of amino acids

polypeptide

long chain of amino acids

enzymes

substances (almost always proteins) that speed up chemical reactions

nucleotides

the monomers of nucleic acids (DNA and RNA)

ATP

adenosine triphosphate, the energy currency of the cell

adenine

the base that pairs with thymine in DNA and uracil in RNA

guanine

the base that pairs with cytosine in DNA and RNA

organelle

a tiny cell structure that carries out a specific function within the cell

plasma membrane

a selectively permeable phospholipid bilayer forming the boundary of the cells

cytoplasm

a jelly-like fluid inside the cell in which the organelles are suspended

simple diffusion

a form of passive transport that does not involve the aid of a carrier protein

facilitated diffusion

a form of passive transport that is aided by transport proteins

passive transport

the movement of a substance across the concentration gradient, which does not require energy

active transport

the movement of a substance against the concentration gradient, which requires energy

osmosis

passive transport (diffusion) of water across a selectively permeable membrane

hypertonic

if a cell is in a _______ solution, the concentration of solutes outside the cell is higher than the concentration inside the cell. the cell will lose water and shrink

hypotonic

if a cell is in a ________ solution, the concentration of solutes inside the cell is higher than the concentration inside the cell. the cell will gain water and swell

isotonic

if a cell is in a _______ solution, the concentration of solutes is equal inside and outside of the cell. the cell will maintain water and shape

endocytosis

in this process, a region of the plasma membrane engulfs the substance to be ingested and then pinches off from the rest of the membrane, forming a vesicle

vesicle

small membrane-bound sac that functions in moving products into, out of, and within a cell

phagocytosis

"cell eating," in which the cell engulfs large particles or bacteria

pinocytosis

"cell drinking," in which the cell engulfs droplets of fluid

exocytosis

the process by which large molecules leave cells. a vesicle from inside the cell fuses with the plasma membrane and spills its contents into the extracellular fluid

nucleus

the organelle which contains almost all of the cell's genetic information

nuclear envelope

a double membrane that surrounds the nucleus and separates it from the cytoplasm

chromosomes

genetic information within the nucleus is organized into these threadlike structures made of DNA and associated proteins

nucleolus

a specialized region within the nucleus that forms and disassembles during the course of the cell cycle

ribosome

the organelle which is the site where protein synthesis begins

endoplasmic reticulum

part of an extensive network of channels connected to the nuclear envelope and certain organelles

smooth endoplasmic reticulum

lacks ribosomes and functions in detoxifying alcohol and other drugs, and producing phospholipids which contribute to membranes

rough endoplasmic reticulum

studded with ribosomes which synthesize proteins, which contribute to membranes

golgi complex

a cell organelle that consists of a series of interconnected, flattened membranous sacs. it processes and packages proteins

lysosome

roughly spherical organelle that digests substances imported from outside the cell and destroys old or defective cell parts

mitochondria

the site of cellular respiration that provides the energy that cells need

cytoskeleton

a network of fibers that holds the cell together, helps the cell to keep its shape, and aids in movement

anabolic pathways

metabolic pathways that consume energy to build complicated molecules from simpler ones

catabolic pathways

metabolic pathways that release energy by breaking down complex molecules into simpler compounds

cellular respiration

the oxygen-requiring pathway by which cells break down glucose to make a total of 36 ATP. consists of 4 phases: glycolysis, transition reaction, citric acid cycle, and electron transport chain

glycolysis

the first phase of cellular respiration, which begins by splitting glucose into smaller sugars, yielding 2 ATP. the only phase which occurs in the cytoplasm

transition reaction

the phase of cellular respiration that links glycolysis and the citric acid cycle, occurs in the mitochondria, and yields 0 ATP

citric acid cycle

the third phase of cellular respiration, which yields 2 ATP and occurs in the mitochondria

electron transport chain

the final phase of cellular respiration, which yields 32 ATP and occurs in the mitochondria

fermentation

the breakdown of glucose without oxygen, which yields only 2 ATP in the entire process

zygote

the cell formed by the union of an egg and a sperm

meiosis

the type of cell division that gives rise to gametes

mitosis

the type of cell division that results in identical body cells

23

the number of chromosomes in a haploid human cell