BIOLOGY IS CONTAGIOUS

116 THINGS YOU NEED TO KNOW TO PASS THE MCAS BIOLOGY EXAM

are mostly made of the elements C,H,O,N,P, and S Living things are mostly made of the elements C,H,O,N,P, and S Organic compounds contain carbon Four important macromolecules are carbohydrates, lipids, proteins, and nucleic acids Polymers are long chains of monomers

The monomer of a protein is an amino acids The monomer of a nucleic acid is a nucleotide A nucleotide consists of a sugar, a phosphate group, and a nitrogenous base The function of a carbohydrate is to provide a cell with energy

Nucleic acids store genetic information for cells Lipids store energy and are a component of cell membranes and are used to produce hormones Proteins have a variety of functions in the cell and make up muscles, hair, and nails Enzymes are proteins that speed up chemical reactions (also known as catalysts) Nucleic acids store genetic information for cells

In a chemical reaction, reactants combine/change to form products Substrates fit into the active site of an enzyme like a “lock in a key” A substrate is a reactant in an enzyme-catalyzed reaction Enzymes work by lowering the activation energy of a chemical reaction

Organelles are the parts of a cell Two things that affect enzyme function are temperature and the pH(acid/base) of a solution Organelles are the parts of a cell Prokaryotes do not have a nucleus; eukaryotes do Plant cells contain cell walls, large vacuoles, and chloroplasts

DNA is found within the nucleus in a eukaryotic cell Animal cells lack a cell well, never have chloroplasts, and contain centrioles DNA is found within the nucleus in a eukaryotic cell Chloroplasts are green and capture sunlight energy to make sugar (glucose) for cells Mitochondria produce energy (ATP) for cells

Ribosomes are the site of protein synthesis The endoplasmic reticulum and the Golgi bodies work together to modify and ship proteins Ribosomes are the site of protein synthesis The cell wall of a plant is made of a carbohydrate (cellulose) and gives plant their rigid shape The cytoskeleton gives the cell shape and structure

Cell membranes are found in all cells and are made of a semi-permeable lipid bilayer Pump and channel proteins are also found in the cell membrane Active transport uses energy (ATP) to move molecules from low concentration to high conc. Active transport requires protein pumps

Facilitated diffusion uses protein channels to move molecules from high conc. to low conc. Diffusion moves small molecules through a membrane from high conc. to low conc. Osmosis is the diffusion of water molecules through a semi-permeable membrane Photosynthesis: 6H2O +6CO2 + light  C6H12O6 +6O2 (occurs in chloroplast)

Cellular Respiration: C6H12O6 +6O2  6H2O +6CO2 + ATP (occurs in mitochondria) Energy in a molecule of ATP is stored in the bonds between phosphate groups The stages of cell division (mitosis) are prophase, metaphase, anaphase, and telophase Cytokinesis causes a cell to divide in two. Animal cells pinch, plant cells assemble membrane and wall

Fertilization is when sperm cells and egg cells join together Gametes (sperm/egg) are made through a two rounds of reductive division called meiosis After mitosis, there is an equal number of chromosomes in each cell (diploid) After meiosis, there is half the normal amount of chromosomes in each cell (haploid) Fertilization is when sperm cells and egg cells join together

Crossing over in meiosis helps increase genetic variation in offspring DNA stores protein instruction in a sequence of nitrogenous bases called a gene The sugar-phosphate backbone gives the DNA molecule structure DNA is a double stranded molecule with a deoxyribose sugar

RNA is a single stranded molecule with a ribose sugar A pairs with T and U ; G pairs with C Three types of RNA: messenger, ribosomal, and transfer RNA contains U instead of T

Replication is when DNA makes an exact copy of itself Transcription is when a gene is copied onto mRNA Translation is when the mRNA transcript is used to make a polypeptide (protein) Mutations can alter a DNA sequence, sometimes (not always) causing a change in the protein

The phenotype is what an organism physically looks like The genotype is what copies of a gene an organism has Alleles are different versions of a gene Dominant alleles mask recessive alleles

A heterozygous individual has two different alleles A homozygous individual has two of the same alleles Blended phenotypes (red + white = pink) show that the alleles are incompletely dominant Mixed phenotypes (orange + blue = orange and blue) show codominant alleles

Evolution is change over long periods of time Polygenic traits are controlled by more than one gene and show a normal (bell) distribution Evolution is change over long periods of time Natural selection states that the best adapted individuals will survive and pass on their genes Evidence for evolution is shown in fossils, DNA sequences, embryology, and homology

Speciation occurs when gene pools become separated over long periods of time Genetic variation among organism comes from crossing over and mutations Organisms are classified by the kingdom, phylum, class, order, family, genus, species system All organisms are descended with changes from an ancient, common ancestor

The three domains are eukarya, archea, and bacteria Polygenic distribution curves can undergo stabilizing, disruptive, or directional selection The three domains are eukarya, archea, and bacteria The six kingdoms are archeabacteria, eubacteria, animalia, plantae, fungi, protista Evolutionary relationships are based on DNA sequences NOT physical appearance

The deeper in a rock layer a fossil is found, the older that Population size is affected by birth rates, death rates, and migration rates. Carrying capacity is the maximum number of individuals an ecosystem can support Limiting factors dictate the size of a population

Producers are autotrophs – they make their own food Ecological organization: species – population – community – ecosystem – biome - biosphere Producers are autotrophs – they make their own food A food web shows all of the feeding relationships in a particular ecosystem Consumers are heterotrophs – they eat their food

Energy arrows always flow from the producers to the consumers Only 10% of the available energy is transferred to the next trophic level The main source of energy for living things is the sun Herbivores are primary consumers

Carbon enters the biosphere through photosynthesis Carbon is returned to the atmosphere by breathing (respiration) and the burning of fossil fuels Carbon enters the biosphere through photosynthesis Bacteria fix nitrogen gas into a form usable by living organisms (nitrogen fixation) Parasitic relationships involve one organism benefiting and the other organism suffering

Mutual relationships show a benefit for both organisms Commensalism shows a benefit for one organism, and no effect for the other Mutual relationships show a benefit for both organisms Homeostasis works via feedback loops and maintains a constant internal environment Carbohydrates, fat, and protein are all important sources of energy and nutrition

Nutrients are absorbed into the blood by the small intestines The stomach and mouth digest (break down) food into smaller molecules using enzymes Nutrients are absorbed into the blood by the small intestines Blood is a suspension of red blood cells, white blood cells, plasma, and platelets The kidneys filter waste materials out of the blood

The heart pumps blood throughout the body Red blood cells carry oxygen, white blood cells fight infection, and platelets clot blood The heart pumps blood throughout the body Veins carry blood to the heart (low oxygen) and arteries carry blood to the body (high oxygen) Lungs contain tiny sacs called alveoli

Air enters the lungs via the trachea (windpipe) Oxygen diffuses into the blood and carbon dioxide diffuses out of the blood at the alveoli Air enters the lungs via the trachea (windpipe) The bolus (mashed food and saliva) enters the stomach via the esophagus The nervous system allows the body to communicate and coordinate functions

There are three types of muscle: skeletal, smooth, and cardiac Neurons consist of a long axon, several short dendrites, and a cell body The endocrine system sends chemical signals (hormones) throughout the body There are three types of muscle: skeletal, smooth, and cardiac Muscles allow the body to move

Bones provide structure and a site for mineral storage Red blood cells are made in bones Viruses are made of a protein coat and genetic material (DNA/RNA). They are not alive! Nerve use electrical impulses and chemical (neurotransmitters) to communicate