9th Grade Honors Bio Midterm Review

source of energy for chemotrophs

chemical reactions from the environment

source of biomolecules for chemotrophs

carbon dioxide from the seawater is fixed into glucose

source of energy for heterotrophs

combusting glucose in the mitochondria

source of biomolecules for heterotrophs

biomolecules are taken from other living things

source of energy for phototrophs

sunlight

source of biomolecules for phototrophs

carbon dioxide from the atmosphere is fixed into glucose

differences between eukaryote, archaea, and bacteria

eukaryotic cells have a nucleus, prokaryotic cells, archaea, and bacteria, do not have a nucleus, but archaea have more similar enzymes and DNA to eukaryotes than bacteria

scientific theory

an explanation of an aspect of the natural world and universe that can be tested using the scientific method

scientific law

statements based on experiments or observations that describe natural phenomena

polar covalent bond

bond that occurs when electrons are not shared equally, the result of this is a dipole, a molecule with both slightly positive and negative ends

hydrogen bonds

bond that is formed between two or more dipoles, molecules with both slight positive and negative ends

what molecules are hydrophilic

polar or ionic molecules, such as sugar

what molecules are hydrophobic

nonpolar molecules, such as oil

what is pH

the concentration of H+ ions in a solution

what is an acid

a solution with a high concentration of H+ ions, with a pH less than 7, such as citric acid

what is a base

a solution with a low concentration of H+ ions, with a pH greater than 7, such as soap

what is an enzyme

a protein that catalyzes a chemical reaction by lowering the activation energy without being used up in the reaction

cell membrane

semi-permeable barrier made of phospholipids, integral and peripheral proteins, carbohydrate chains, and cholesterol(in animals)

nucleus

double-membrane sac that holds DNA, continuous with the ER and studded with nuclear pores

nucleolus

dark mass inside the nucleus where mRNA and ribosomal proteins are read

rough er

tubes of membrane studded with ribosomes, site of protein synthesis for exported proteins

smooth er

same as rough ER but without ribosomes

golgi bodies

thin bubbles of membrane in a stack that put final modifications on exported proteins, packages them into vesicles

mitochondria

double membrane organelle with a folded inner membrane called the cristae, site of the krebs cycle and etc, source of most atp used by the cell, believed to have been a free living bacteria by the endosymbiotic theory

chloroplast

double membrane organelle with thylakoid stacks called grana, site of light reactions and calvin cycle of photosynthesis, believed to have been a free living bacteria by the endosymbiotic theory

cytoskeleton

internal skeleton that gives cell shape and support, made of microtubules and actin fibers

cell wall

protects cell against osmotic shock, made of cellulose for plants, chitin for fungi, and peptidoglycan for prokaryotes

large central vacuole

found only in plant cells, filled with water so cells are constantly pushing against the cell wall

plasmodesmata

tunnels between cell membranes and plant cell walls, allowing the sharing of cytosol

exported protein path

mRNA exits nucleus through pores and binds to ribosome on rough er, the protein is made and travels to the smooth er, bubbles off in a vesicle to the golgi bodies, golgi bodies modify proteins as needed, proteins bubble off in a vesicle again, vesicle moves to and fuses with membrane, pushing the proteins out

cytosolic protein path

mRNA exits the nucleus through pores, finds a cytosolic ribosome, protein is made and remains in the cytosol

how is the cell membrane technically made of recycled golgi bodies

the vesicles that bubble off the golgi bodies and carry the exported proteins, fuses with the membrane in order to push the proteins out the cell