Biology Final Exam Study Guide

Nucleus

command center of the cell, contains DNA

Mitochondria

generates ATP energy through cellular respiration

Ribosomes

synthesize proteins, either float freely in the cytoplasm or attack to the endoplasmic reticulum

Endoplasmic Reticulum

Network of membranes - Rough ER has ribosomes and synthesizes proteins

Golgi Apparatus

modifies sorts, and packages proteins

Cytoplasm/Cytosol

The jelly-like fluid that supports organelles and gives the cell shape

Cytoskeleton

Network of protein fibers structurally supporting the cell

Cell Membrane

a selectively permeable barrier that controls the movement of substances in and out of the cell

Cell Wall (JUST PLANTS)

rigid outer layer of cellulose providing structural support and protection

Chloroplasts (JUST PLANTS)

contains chlorophyll and converts sunlight into sugar through photosynthesis

Central Vacuole (JUST PLANTS)

massive storage sac holding water and nutrients, exerts internal pressure (tugor) to keep the plant upright

Centrosomes (JUST ANIMALS)

structures used during mitosis

Lysosomes (JUST ANIMALS)

waste disposal units containing digestive enzymes to break down old cell parts and foreign invaders

Microfilaments/Microtubules

Structures that are part of the cytoskeleton (microtubules also play an important role in mitosis)

Lipid bilayer

makes up the cell membrane and gives it a flexible structure and a strong barrier

Selectively permeable

cell membranes are selectively permeable, meaning that some substances can pass through it and others can’t - small, uncharged, nonpolar substances have an easy time passing through

homeostasis

the state of relatively constant internal physical and chemical conditions - cells maintain this by regulating the movement of molecules and other substances from one side of the membrane to the other

Diffusion

the process by which particles move from an area of higher concentration to an area of lower concentration (passive transport)

Passive transport

the movement of molecules across the cell membrane without using cellular energy

facilitated diffusion

large/charged molecules diffuse across the membrane through special protein channels (passive transport)

Aquaporins

water channel proteins that allow for the diffusion of water through the cell membrane

Osmosis

the diffusion of water through a selectively permeable membrane (either through an aquaporin or directly through the cell membrane). During this process, molecules move from an area of higher concentration to an area of lower concentration until equilibrium is reached.

Isotonic solutions

two solutions that are of the same strength

Hypertonic solutions

solutions that are above strength compared to the solution on the other side

Hypotonic solutions

solutions that are below strength compared to the other side

Osmotic pressure

the force produced by the net movement of water in or out of a cell, and it can cause an animal cell in a hypertonic solution to shrink and one in a hypotonic solution to swell - in plant cells, osmotic pressure can cause changes to the size of the central vacuole

Active transport

the movement of materials against a concentration difference which requires energy

Protein pumps

These transport ions and small molecules through the membrane via active transport

Endocytosis (Bulk Transport)

the process of taking material into the cell by infolding of the cell membrane - the pocket that results breaks loose from the cell membrane and forms a vesicle/vacuole within the cytoplasm

Phagocytosis (Bulk Transport)

a form of endocytosis where extensions of cytoplasm surround a particle and package it within a food vacuole and then engulf it

Exocytosis (Bulk Transport)

a process to release large amounts of material, when the membrane of the vesicle/vacuole fuses with the cell membrane, forcing the contents out of the cell

ATP

an important compound that stores and releases energy - used for active transport, cell movement, light, and other processes

Chlorophyll

a pigment used by plants to capture the energy from sunlight

Thylakoids

saclike chlorophyll containing membranes that are inside the chloroplast and arranged in stacks

Grana

stacks of thylakoids inside chloroplasts

Stroma

the fluid portion of the chloroplast outside of the thylakoids

electron carrier

a compound that can accept a pair of high-energy electrons and transfer them from the chlorophyll, along with most of their energy, to another molecule

NADP+/NADPH

NADP+ is one of the carrier molecules, which is converted into NADPH after accepting and holding 2 electrons and a hydrogen ion - after conversion, the NADPH carries the electrons elsewhere in the chloroplasts

Photosynthesis Formula

Carbon Dioxide + Water + Sunlight → Sugars + Oxygen (6CO2 + 6H2O + Sunlight → C6H12O6 + 6O2)

light-dependent reactions

the first set of reactions in photosynthesis that occur in the thylakoids and convert ADP into ATP and NADP+ into NADPH

light-independent reactions

the second set of reactions in photosynthesis, where the ATP and NADPH build high-energy sugars from carbon dioxide, and these reactions take place in the stroma of the chloroplast

Cellular Respiration Formula

oxygen + glucose → carbon dioxide + water + energy (6O2 + C6H12O6 → 6CO2 + 6H2O + energy)

3 stages of cellular respiration

glycolysis (anaerobic), the Krebs cycle (aerobic), and electron transport chain (aerobic)

Aerobic

A process that requires oxygen

Anaerobic

A process that doesn’t require oxygen

fermentation

a process of glycolysis combined with a pathway that happens when there’s no oxygen present - fermentation releases ATP from food molecules

alcoholic fermentation

carried out by yeast - formula: pyruvic acid + NADH → alcohol + CO2 + NAD+

lactic acid fermentation (when does it happen?)

in humans, during brief periods of a lack of oxygen, ATP is often produced through this process, with muscle cells often doing this during bursts of activity

Nucleotides

the monomers of nucleic acids

amino acids

the monomers of proteins

peptide bonds

the covalent bonds between amino acids - they form through dehydration synthesis, where a water molecule is released as the amino acids form a bond

polypeptides

chains of amino acids - proteins are made of folded polypeptide chains

nitrogenous bases

DNA is made up of 4 nitrogenous bases: A-T and G-C, which are bonded through hydrogen bonds. In any sample of DNA, the percentage of each base will be the same as its pair

DNA replication

during synthesis, replication occurs, where the 2 strands of each DNA molecule separate and 2 new strands are synthesized following the rules of base pairing

DNA replication enzymes

during replication, enzymes “unzip” a DNA molecule by breaking the hydrogen bonds between base pairs and unwinding the strands. Then, DNA polymerase joins nucleotides to synthesize a new complementary strand of DNA

Replication in prokaryotic vs. eukaryotic cells

prokaryotic: in most cells, replication starts from a single point and proceeds in 2 directions until the entire chromosome is copied

eukaryotic: in most cells, replication might begin at hundreds of places on the DNA molecule, proceeding in both directions until each chromosome is completely copied