week 7 test Flashcards
atomic number
the number of protons in the nucleus of an atom
condensation
change of state from a gas to a liquid
covalent bond
a chemical bond that involves sharing a pair of electrons between atoms in a molecule. Electrons are shared equally.
double bond
the sharing of two pairs of electrons by 2 atoms
electron shell
an energy level of electrons at a characteristic average distance from the nucleus of an atom
electronegativity
the ability of an atom to attract electrons when the atom is in a compound
gene
a segment of DNA on a chromosome that codes for a specific trait
hydrogen bond
a type of weak chemical bond formed when a slightly positive hydrogen atom of a polar covalent bond in one molecule is attracted to the slightly negative atom of a polar covalent bond in another molecule
hydrophilic
water loving
hydrophobic
having an aversion to water; tending to coalesce and form droplets in water
hydrophobic interactions
a type of weak chemical interaction caused when molecules that do not mix with water coalesce to exclude water
cation
positively charged ion
anion
negatively charged ion
non-polar
molecule in which all atoms have the same electronegativity and the electron distribution is equal
polar covalent bond
a covalent bond between atoms that differ in electronegativity. The shared electrons are pulled closer to the more electronegative atom, making it slightly negative and the other atom slightly positive
van der waals forces
a slight attraction that develops between the oppositely charged regions of nearby molecules
4 KEY CHARACTERISTICS OF LIVING ORGANISMS
Complexity
Ability to respond to the environment
ability to reproduce
capacity to evolve
complexity
precise spatial organisation / cellular structure
3 features of the cell
- stores and transfers genetic information
- enclosed in a membrane
- undergoes metabolism
evolution
gradual change in a species over time
homeostasis
a tendency to maintain a balanced or constant internal state; the regulation of any aspect of body chemistry, such as blood glucose, around a particular level
properties of water
- Ability to have hydrophilic reactions (great solvent)
- hydrophobic reactions (allow for shaping (think cell membrane))
- highly cohesive (sticks together)
- solid water is more dense than liquid water
- high heat capacity
- high heat of evaporation
prion
a misfolded protein that causes disease
giruses
giant virus
acid
A molecule that releases a proton. <7 acid
base
a molecule that accepts a proton -> pH
Alpha helix
a spiral shape constituting one form of the secondary structure of proteins, arising from a specific hydrogen-bonding structure
beta pleated sheet
one form of the secondary structure of proteins in which the polypeptide chain folds back and forth, or where 2 regions of the chain lie parallel to each other and are held together by hydrogen bonds
activation energy
the minimum amount of energy required to start a chemical reaction
allosteric
the binding of a regulatory molecule to a protein at one site that affects the function of the protein at a different site
amino acid
compound with an amino group on one end and a carboxyl group on the other end
ATP
(adenosine triphosphate) main energy source that cells use for most of their work
cellulose
a substance (made of sugars) that is common in the cell walls of many organisms
chemical energy
a form of potential energy that is stored in chemical bonds between atoms
coenzyme
an organic cofactor
cofactor
a nonprotein molecule or ion that is required for the proper functioning of an enzyme
complementary bases
2 bases that pair together. A is complementary to T and C is complementary to G
condensation reaction
a reaction in which 2 molecules become covalently bonded to each other through the loss of a small molecule, usually water, also called a dehydration reaction
disaccaride
a double sugar formed from 2 monosaccharides (sugar)
double helix
2 strands of nucleotides wound about each other; structure of DNA
endergonic
a chemical reaction that requires input of energy in order to proceed
energetic coupling
the driving of a non-spontaneous reaction by a spontaneous reaction
enzyme-substrate complex
a temporary complex formed when an enzyme binds to its substrate molecule(s)
exergonic
chemical reactions that release energy
fatty acid
an organic acid that is contained in lipids, such as fats or oils
galactose
a monosaccharide found, along with lactose, in dairy products, and is synthesised by the body where it’s found associated with glycolipids and glycoproteins
gibbs free energy
the energy of a system that is available to do work at a constant temperature and pressure
glucose
simple sugar that is an important source of energy
glycogen
an extensively branched glucose storage polysaccharide found in the liver and muscle of animals; the animals equivalent of starch
glycosidic bond
a glycosidic bond is a covalent bond in which a carbohydrate binds to another group, which could also be a carbohydrate. A glycosidic bond is found between 2 glucose molecules in maltose
kinetic energy
the energy an object has due to its motion
lactose
glucose + galactose
lipid
Macromolecule made mostly from carbon and hydrogen atoms; includes fats, oils and waxes
macromolecule
very large organic molecule composed of many smaller molecules
monomer
single compound whose molecules can join together to form polymers
monosaccharide
a single sugar molecule such as glucose or fructose, the simplest form of sugar
nucleic acid
macromolecule containing hydrogen, oxygen, nitrogen, carbon and phosphorous
nucleotide
monomer of nucleic acids made up of 5-carbon sugar, phosphate group and nitrogenous base
peptide bond
the chemical bond that form between the carboxyl group of one amino acid and amino group of another amino acid
phospholipid
a lipid that contains phosphorous and that is a structural component in cell membranes
phosphodiester bond
type of bond that links the nucleotides in DNA or RNA. Joins the phosphate group of one nucleotide to the hydroxyl group on the sugar of another nucleotide
polymer
a long molecule consisting of many similar or identical monomers linked together
polypeptide
a polymer (chain) of many amino acids linked together by peptide bonds
polysaccharide
carbohydrates that are made up of more than 2 monosaccharides
potential energy
stored energy that results from the position or shape of an object
primary structure
the first level of protein structure; the specific sequence of amino acids making up a polypeptide chain
protein
an organic compound that is made of one or more chains of amino acid and that is a principal component of all cells
purine
a nitrogenous base that has a double-ring structure; one of the two general categories of nitrogenous bases found in DNA and RNA; either adenine or guanine
pyrimidine
a nitrogenous base that has a single-ring structure; one of the 2 general categories of nitrogenous bases found in DNA and RNA; thymone, cytosine or uracil
quaternary structure
the particular shape of a complex, aggregate protein, defined by the characteristic 3 dimensional arrangement of its constituent subunits, each a polypeptide
ribose
a 5 carbon sugar present in RNA
RNA
a single stranded nucleic acid that contains the sugar ribose
saturated fats
a fat that is solid at room temperature and found in animals fats, lards and dairy products
secondary structure
the second level of protein structure; the regular local patterns of coils or folds of a polypeptide chain
starch
a storage polysaccharide in plants consisting entirely of glucose
substrate
a specific reactant acted upon by an enzyme
tertiary structure
the third level of protein structure; the overall, three-dimensional shape of a polypeptide due to interactions of the R groups of amino acids making up the chain
triglyceride
a lipid made of three fatty acid molecules and one glycerol molecule
unsaturated fats
a fat that is liquid at room temp
active transport
energy requiring process that moves material across a cell membrane against a concentration difference
adaption
heritable characteristic that increases an organism’s ability to survive and reproduce in an environment
amphipathic
a molecule that has both a hydrophilic and hydrophobic region
archea
domain of unicellular prokaryotes that have cell walls that don’t contain peptidoglycan
channel protein
a membrane protein, specifically a transport protein, that has a hydrophilic channel that certain molecules or atomic ions use as a tunnel
cholesterol
a lipid that forms an essential component of animal cell membranes and acts as a precursor molecule for the synthesis of other biologically important steroids.
concentration gradient
difference in the concentration of a substance from one location to another
diffusion
movement of molecules from an area of higher concentration to an area of lower concentration
DNA damaging agent
Environmental agents such as UV light, ionizing radiation, and genotoxic chemicals. Replication forks can be stalled due to damaged DNA and double strand breaks are also a form of DNA damage
electrochemical gradient
the diffusion gradient of an ion representing a type of potential energy that accounts for both the concentration difference of the ion across a membrane and its tendency to move relative to the membrane potential
eukaryote
a cell that contains a nucleus and membrane bound organelles
extremophile
a microorganism, especially an archaean, that lives in conditions of extreme temperature, acidity, alkalinity, or chemical concentration
facilitated diffusion
movement of specific molecules across cell mebranes through protein channels
genome
all the genetic information in an organism; all of an orgnaism’s chromosomes
genotype
an organism’s genetic makeup, or allele combinations
halophile
an organism that can grow in, or favours environments that have very high salt concentrations
horizontal gene transfer
the transfer of genes from one genome to other through mechanisms such as transposable elements, plasmid exchange, viral activity and perhaps fusions of different organisms
hypertonic
when comparing 2 solutions, the solution with greater concentration of solutes
hypotonic
when comparing 2 solutions, the solution with the lesser concentration of solutes
isotonic
describes a soltuion whose solute concentration is equal to the solute concentration inside a cell
membrane
thin layer of tissue covering a structure or cavity
mutagenesis
the creation of a change in the nucleotide sequence of an organism’s DNA
mutation
changes in a DNA sequence that affects genetic information
nitrogen source
for proteins, DNA, RNA, ATP
osmoregulation
regulation of solute concentrations and water balance by a cell or organism
osmosis
diffusion of water across a selectively permeable membrane
passive transport
the movement of substances across a cell membrane without the use of energy by the cell
phospholipid bilayer
a double layer of phospholipids that makes up plasma and organelle membranes
phenotype
the set of observable characteristics of an individual resulting from the interaction of its genotype with the environment
phylogenetic tree
diagram showing evolutionary relationships of organisms with a common ancestor; resembles a tree
plasma membrane
a microscopic membrane of lipids and proteins that forms the external boundary of the cytoplasm of a cell or encloses a vacuole, and that regulates the passage of molecules in and out of the cytoplasm
prokaryote
a unicellular organism that lacks a nucleus and membrane bound organelles
selective permeability
a property of a plasma membrane that allows some substances to cross more easily than others
transport protein
a transmembrane protein that helps a certain substance or class of closely related substances to cross the membrane
compartmentalisation
the separation of cellular activities into various compartments or organelles inside the cell
cyanobacteria
photosynthetic, oxygen producing bacteria (formerly known as blue-green algae)
endomembrane system
a network of membranes inside and around a eukaryotic cell, related either through direct physical contact or by the transfer of membranous vesicles
endosymbiosis
a theorized process in which early eukaryotic cells were formed from simpler prokaryotes
FECA
first eukaryotic common ancestor, no chloroplast
LECA
last eukaryotic common ancestor
vesicle
a membrane bound sac that contains materials involved in transport of the cell
lysosome
cell organelle filled with enzymes needed to break down certain materials in the cell
golgi body
a structure in a cell that receives proteins and other newly formed materials from the endoplasmic reticulum, packages them and distributes them to other parts of the cell
rough endoplasmic reticulum
system of internal membranes within the cytoplasm. Membranes are rough due to the presence of ribosomes. Functions in transport of substances such as proteins within the cytoplasm
smooth endoplasmic reticulum
an endomembrane system where lipids are synthesized, calcium levels are regulated and toxic substances are broken down
signal recognition protein
secretory proteins synthesized on membrane bound ribosomes have their signal sequence recognized by this
plasmid
small ring of DNA that carries accessory genes separate from those of the bacterial chromosome
nucleoid
a non-membrane bounded region in a prokaryotic cell where the DNA is concentrated
PILI
Appendages that allow bacteria to attach to each other and to transfer DNA
Peroxisomes
break down fatty acids and produce hydrogen peroxide
nuclear envelope
layers of 2 membranes that surrounds the nucleus of a cell
lumen
space within a tubular part or organ such as the space within a blood vessel
signal anchor sequence
if a polypeptide chain has this sequence, it will end up embedded in the membrane. If not, it will end up in the lumen of the ER, Golgi, lysosome or exterior of the cell
cisternae
flattened, membrane-bound compartments that make up the golgi apparatus
protein sourcing
the process by which proteins end up where they need to be in the cell to perform their function
signal sequences
an amino acid sequence that directs a protein to its proper cellular compartment
nuclear localisation signals
the signal sequence for the nucleus that enables proteins to move through pores in the nuclear envelope
amino terminal signal
chloroplast and mitochondria
accessory pigments
pigment that absorbs light at different wavelengths and then pass energy onto chlorophyll
anoxygenic photosynthesis
light-fueled conversion of co2 to organic material that does not produce oxygen
calvin cycle
reactions of photosynthesis in which energy from ATP and NADPH is used to build high-energy compounds such as sugars
carboxylation
the first step of calvin cycle, in which co2 absorbed from the air is added to a 5-carbon molecule
chlorophyll
green pigment in plants that absorbs light energy used to carry out photosynthesis
chloroplasts
organelles that capture the energy from the sunlight and convert it to chemical energy through photosythesis
electron donor
a reactant that loses an electron and is oxidized in a reduction oxidation reaction
electron transport chain photosynthesis
electrons move through several transmembrane proteins that are responsible for pumping H+ ions across the membrane, creating the chemical gradient across the chloroplast membrane. Energy source is captured light, part of the light reactions
grana
stack of thylakoids embedded in the stroma of a chloroplast
light dependent reaction
set of reactions in photosynthesis that use energy from light to produce ATP and NADPH
NADPH
An electron carrier involved in photosynthesis. Light drives electrons from chlorophyll to NADO+, forming NADPH, which provides the high-energy electrons for the reduction of CO2 to sugar in the calvin cycle
oxidation
the loss of electrons from a substance involved in a redox reactions
oxygenic photosynthesis
photosynthesis that oxidizes water to form oxygen; the form of photosynthesis characteristic of plants, protists and cyanobacteria
photoautotroph
an organism that harnesses light energy to drive the synthesis of organic compounds from co2
photosystems
proteins in the thylakoid membrane organize chlorophyll and other pigments into clusters
reaction centre
a transmembrane protein complex containing chlorophyll a whose electrons absorb light energy and begin the process of photosynthesis
redox reactions
a chemical reaction involving the transfer of one or more electrons from one reactant to another; also called oxidation-reduction reaction
reduction
gain of electrons
regeneration
replacement of destroyed tissue by the same kind of cells
rubsico
enzyme that converts inorganic co2 molecules into organic molecules during the final step of the calvin cycle
stroma
the fluid of the chloroplast surrounding the thylakoid membrane; involved in the synthesis of organic molecules from co2 and water
thylakoid membrane
the photosynthetic membrane within a chloroplast that contains light gathering pigment molecules and electron transport chains
visible light
electromagnetic radiation that can be seen with the unaided eye
wavelengths
the distance between the arrival of peaks of a light wave; shorter wavelengths = higher frequency
ADP
(Adenosine Diphosphate) The compound that remains when a phosphate group is removed from ATP, releasing energy
anabolism
Constructive metabolism; the process of building up larger molecules from smaller ones.
anaerobic respiration
Respiration that does not require oxygen
ATP synthase
Large protein that uses energy from H+ ions to bind ADP and a phosphate group together to produce ATP
catabolism
Metabolic pathways that break down molecules, releasing energy.
cellular respiration
Process that releases energy by breaking down glucose and other food molecules in the presence of oxygen
chemoautotroph
organism that makes organic carbon molecules from carbon dioxide using energy from chemical reactions
chemoheterotroph
An organism that must consume organic molecules for both energy and carbon.
citric acid cycle
Completes the breakdown of glucose by oxidizing a derivative of pyruvate to carbon dioxide.
electron acceptor
A reactant that gains an electron and is reduced in a reduction-oxidation reaction.
electron carrier
a compound that can accept a pair of high-energy electrons and transfer them, along with most of their energy, to another molecule
electron transport chain
A sequence of electron carrier molecules (membrane proteins) that shuttle electrons during the redox reactions that release energy used to make ATP.
FADH-
A molecule that stores energy for harvest by the electron transport chain.
FADH2
electron carrier produced during the Krebs cycle
GLYCOLYSIS
A metabolic process that breaks down carbohydrates and sugars through a series of reactions to either pyruvic acid or lactic acid and release energy for the body in the form of ATP
METABOLISM
the combination of chemical reactions through which an organism builds up or breaks down materials
MITOCHONDRIA
Cell organelle that converts the chemical energy stored in food into compounds that are more convenient for the cell to use
NAD+
(nicotinamide adenine dinucleotide) electron carrier involved in glycolysis
NADH
the reduced form of NAD+; an electron-carrying molecule that functions in cellular respiration
OXIDATIVE PHOSPHORYLATION
The production of ATP using energy derived from the redox reactions of an electron transport chain; the third major stage of cellular respiration.
PHOTOHETEROTROPH
organism that is photosynthetic but needs organic compounds as a carbon source
PROTON GRADIENT
The product of the electron transport chain. A higher concentration of protons outside the inner membrane of the mitochondria than inside the membrane is the driving force behind ATP synthesis.
PYRUVATE
Three-carbon compound that forms as an end product of glycolysis.
PHOTOAUTOTROPH
organisms that can utilize light energy from sunlight and elements (such as carbon) from inorganic compounds to produce organic materials needed to sustain their own metabolism
e.g plants, cyanobacteria
