BIOLOGY KEYSTONE REVIEW

scientific method

scientific method

observe, hypothesize, experiment, gather data, analyze results, present findings, repeat

metric system

the system always used in science

the United States is the only country that doesn't use it (:

controlled experiment

an experiment in which only one variable is altered

independent variable

the variable that you have control over ("I" control the "I"ndependent variable)

dependent variable

the variable that you measure

theory

a well-tested explanation that has never been proven incorrect

8 characteristics of life

made of cells, reproducing, DNA, growing and developing, response to environment, maintain homeostasis, obtain materials and use energy, and change over time

atom

basic unit of matter

proton

one of the three things that make up atoms (positive charge)

found in the nucleus

neutron

one of the three things that make up atoms (no charge)

found in the nucleus

electron

one of the three things that make up atoms (negative charge)

found orbiting the nucleus

element

comprised of only one type of atom

compounds

comprised of two or more elements that are chemically combined

covalent bond

occurs when atoms equally share electrons

ionic bond

occurs when one atom steals electrons from another

can be positively or negatively charged

properties of water (H2O)

polar covalent molecule, universal solvent, has a specific heat (that allows it to act as an insulator), when water freezes it expands (allowing ice to be less dense than water)

cohesion

occurs when molecules of the same substance are attracted

adhesion

occurs when molecules made of different substances are attracted

pH scale

ranges from 1-14 to measure how acidic or basic a substance is (with 7 being neutral)

buffer

weak acids or bases that neutralize stomach acid to maintain a comfortable environment for an organism

carbon

element found in all living things due to its 4 valence electrons

monomer

subunits forming polymers

polymer

(AKA macromolecule)

formed with monomers

condensation/dehydration reaction

occurs a polymer and releases water

hydrolysis reaction

occurs when water is used to break apart a polymer into its original monomers

4 major macromolecules

carbohydrates, proteins, lipids, nucleic acids

carbohydrates

sugars made of carbon, hydrogen, and oxygen in a 1:2:1 ratio

monomer: glucose (monosaccharide)

lipids

energy molecules in oils, fats, and waxes

also part of the cell membrane (phosphoLIPID bilayer)

monomer: fatty acids

nucleic acids

used in DNA and RNA

monomer: nucleotides

proteins

used for building and catalysts

monomer: amino acids

enzyme

act as biological catalysts

reaction rates are impacted by temperature, pH, and substrate concentration

denatured protein

occurs when the temperature and pH of a protein is impacted enough to change the shape of said protein

activation energy

the amount of energy necessary for a chemical reaction to begin

homeostasis

in order to maintain this, all reactions in an organism are necessary

cell

the basic unit of life

differentiation

word to describe how cells are specialized in how they look based on their function

(nerve cells, etc)

microscope

tool used in science that was the key in discovering the cell in the first place

cell theory

1. all living things are made of cells

2. cells are the basic unit of structure and function

3. cells come from other cells

prokaryotic cell

lack nucleus and membrane-bound organelles, have cytoplasm, plasma membrane, cell wall, DNA, and ribosomes

examples include bacteria

eukaryotic cell

has nucleus and membrane bound organelles, a plasma membrane, cytoplasm, DNA, ribosomes, endoplasmic reticulum, golgi apparatus, nucleolus within the nucleus, vacuoles, a cell wall (in some)

examples include animals, plants, fungus, protists

nucleus

organelle that contains genetic information

rough endoplasmic reticulum

organelle that contains ribosomes to make proteins

smooth endoplasmic reticulum

organelle that makes lipids and is involved in detoxification

golgi apparatus

organelle that adds finishing touches to proteins

ribosome

organelle that makes proteins

lysosome

organelle that contains enzymes to break down polymers

peroxisome

organelle that contains enzymes involved in chemical reactions

vacuole

organelle that stores water, enzymes, etc

nucleolus

organelle that makes ribosomes

mitochondria

organelle that is the powerhouse of the cell and makes ATP

chloroplast

organelle that makes food for plants

cytoskeleton

organelle that is the skeleton- made of protein fibers of microfilaments (thin) and microtubules (thick)

cell membrane

organelle that provides protection and a pathway for materials to travel in and out of the cell

goes by many names: fluid mosaic model, plasma membrane, phospholipid bilayer

phospholipid

contains two regions:

hydrophilic - the head

hydrophobic - the tail (scared of water)

cell wall

organelle that is a sugar/protein boundary layer in plant cells

diffusion

the movement of molecules from high to low concentration

no energy required

osmosis

diffusion of water across a membrane

no energy required

facilitated diffusion

diffusion with the help of proteins

no energy required

active transport

movement of molecules from a low to high concentration

requires energy

endocytosis

movement of a large substance into a cell

example of active transport

exocytosis

movement of a large material out of a cell

example of active transport

sodium-potassium pump

one of the most important carrier proteins in animal cells

used to generate gradients of sodium and potassium ions in nerve cells

photosynthesis

the chemical process in which plants make their own food

powered by energy from the sun

creates the molecule adenosine triphosphate (ATP)

equation:

6CO2, 6H2O, + Light ->(yields) C6H12O2, + 6O2

autotroph

producers, can make their own food

heterotroph

consumers that rely on other living things for food

Light Reactions

in this process, pigments such as chlorophyll absorb sunlight to provide enough energy to excite electrons

one of the two main processes of photosynthesis

releases oxygen as a byproduct and introduces ATP and NADPH

Calvin Cycle

light is no longer directly required

occurs in the stroma

glucose is formed

NAPDH converted into NADP+ and ATP into ADP + P

cellular respiration

how living things obtain ATP energy from glucose

glycolosis

occurs in the cytoplasm

the splitting of glucose

one of the 3 processes in cellular respiration

Krebs Cycle (Citric Acid Cycle)

occurs in the mitochondria matrix

produces carbon dioxide and the energy carriers NADH, ATP, and FADH2

one of the 3 processes in cellular repiration

Electron Transport Chain

occurs in the membrane of the mitochondria

produces the most ATP molecules in the process (36 in the whole process)

one of the 3 processes in cellular respiration

anaerobe

organism that doesn't need oxygen

fermentation

occurs when oxygen isn't required for cellular respiration

typically only produces 2 ATP molecules

alcoholic fermentation

alcohol is produced

occurs in rising of bread

lactic acid fermentation

lactic acid is produced

occurs when muscles cramp up in humans (as an example)

cell cycle

involves all aspects related to cell growth including interphase and mitosis

interphase

growth phase for cells in which the cell prepares to divide by making more cytoplasm, organelles, and proteins

has three phases: G1, S, and G2

phases allow for check points

if problem is found at check point, cell enters G0 phase and gets recycled

cancer

occurs when a cell divides uncontrollably

mitosis

cell division with the goal of making two identical cells (including an equal number of organelles, chromosomes, and cytoplasm)

starts with 92 chromosomes and each cell ends with 46 chromosomes

prophase

longest phase of mitosis where chromosomes are visible, centrioles separate, the nuclear membrane breaks down, and spindle fibers form

metaphase

phase of mitosis where chromosomes line up in the middle of the cell and their centromeres are connected to the spindle fibers

anaphase

phase of mitosis where centrioles pull the spindle fibers to seperate the chromosomes to opposite sides of the cell

telophase

phase of mitosis where the nuclear membrane reforms, spindle fibers disappear, and cytokinesis (cytoplasm division) occurs

cleavage furrow

forms at the end of telophase to divide the cells in animals

cell plate

forms at the end of telophase to divide the cells in plants

binary fission

process of cell division that bacteria undergo

DNA strand replicates and the cell divides in half

meiosis

cell division that creates gametes (sex cells)

cell starts with 92 chromosomes and ends with 4 gametes that contain 23 chromosomes each

divided between meiosis 1 and meiosis 2

meiosis 1

crossing over occurs in which homologous chromosomes exchange pieces of DNA (prophase 1)

meiosis 2

cell does not undergo chromosome replication

in anaphase 2, chromatids seperate

Gregor Mendel

Father of Genetics

genetics

study of heredity

traits

specific characteristics

gene

DNA that codes of a trait

alleles

alternate versions of a trait found on a gene

dominant alleles

always expressed when present

recessive alleles

only expressed if an organism that two copies of the recessive allele

probability

the likelihood of a specific event occuring

Punnett Square

tool used to predict the probability of offspring having inherited genotypes

homozygous

both alleles are dominant or

both alleles are recessive

heterozygous

an organism has two different alleles