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How do hydrogen bonds form?
negative oxygen end of one water molecule is attracted to the positive hydrogen end of another water molecule; responsible for most properties of water
cohesion
Attraction between molecules of the same substance
adhesion
An attraction between molecules of different substances
capillary action
the combined force of attraction among water molecules and with the molecules of surrounding materials
high specific heat
A property of water. Water can absorb lots of heat before changing temperature
water is less dense as a solid
ice expands as it freezes so it floats
hydroxyl group
OH-
carbonyl group
C=O
carboxyl group
COOH
amino group
NH2
phosphate group
PO4
dehydration synthesis
A chemical reaction in which two molecules are bonded together with the removal of a water molecule.- makes polymers
Hydrolysis
A chemical process that splits a molecule by adding water. breaks down polymers
monomer of carbs
monosaccharides
monomer of lipids
glycerol and fatty acids
monomer of protein
amino acid
monomer of nucleic acids
nucleotides
examples of carbohydrate polymers
starch, cellulose, glycogen
examples of lipid polymers
Triglycerides, Phospholipids, Steroids,
examples of nucleic acid polymers
DNA and RNA
example of protein polymer
polypeptide
what determines the primary structure of a protein
sequence of amino acids
secondary structure of protein
coils and folds due to the hydrogen bonding within the polypeptide backbone
tertiary structure of protein
3D folding due to interactions between the side chains of the amino acids
quaternary structure of protein
results when a protein consists of multiple polypeptide chains
components of a nucleotide
nitrogenous base, phosphate, pentose sugar
how are DNA and RNA different
DNA: deoxyribose, double strand, and thymine
RNA: ribose, single strand, and uracil
Differences between prokaryotic and eukaryotic cells
Prokaryotes- no nucleus (DNA found in nucleoid region), no membrane bound organelles, smaller, one circular chromosomes, bacteria. Eukaryotes- nucleus, organelles, larger, many linear chromosomes, plants and animals
path of protein to final product
mRNA produced in nucleus-- ribosome-- Rough ER-- Golgi-- Vesicle
ribosome
Makes proteins
rough ER
A network of interconnected membranous sacs in a eukaryotic cell's cytoplasm; covered with ribosomes that make membrane proteins and secretory proteins.
Smooth ER
makes lipids and detoxifies the cell
Golgi
A system of membranes that modifies and packages proteins for export by the cell
Lysosome
cell organelle filled with enzymes needed to break down certain materials in the cell
vacuole
Cell organelle that stores materials such as water, salts, proteins, and carbohydrates
mitochondria
breaks down glucose into ATP
chloroplast
converts sunlight into glucose
what happens to the surface area to volume ratio as a cell grows?
decreases
Do you want a large or small SA:V ratio?
high
What adaptations do cells have to increase their ratio
Developing folds (mitochondria membrane), projections (microvilli on intestinal cells), elongated shapes
What molecule embeds itself within the membrane and affects fluidity?
cholesterol
what type of molecules are able to pass through the membrane?
small, nonpolar, and hydrophobic
passive transport
the movement of substances across a cell membrane without the use of energy by the cell; moves substances down the concentration gradient
active transport
Energy-requiring process that moves material across a cell membrane against a concentration difference
facilitated diffusion
passive transport that requires a channel or carrier protein
hypertonic solution
A solution in which the concentration of solutes is greater than that of the cell that resides in the solution; cell will lose water and shrink
isotonic solution
A solution in which the concentration of solutes is essentially equal to that of the cell which resides in the solution; cell stays same size
hypotonic solution
A solution in which the concentration of solutes is less than that of the cell that resides in the solution; cell gains water and will burst if animal cell
active site
the region on the enzyme where the substrate binds
substrate
reactant of an enzyme-catalyzed reaction
allosteric site
A specific receptor site on some part of an enzyme molecule remote from the active site.
how do enzymes speed up chemical reactions?
by lowering the activation energy
competitive inhibition
Inhibitor competes with substrate for active site.
noncompetitive inhibition
inhibitor binds elsewhere on the enzyme; changes shape of active site so that the substrate cannot bind
where do light independent (Calvin Cycle) reactions occur?
stroma of the chloroplast
where do light dependent reactions occur?
thylakoid membrane of the chloroplast
what is produced in the light reactions?
ATP and NADPH
How are electrons lost from photosystem II replaced?
splitting water; oxygen is released in the process
what is the hydrogen gradient created in the light reactions used to do?
used by ATP synthase to create ATP
what are the products of the light reaction used for in the Calvin cycle?
provide energy for glucose production
Where does glycolysis occur?
cytoplasm
how many ATPs are produced during glycolysis
2 ATP
Where does the Krebs cycle occur?
mitochondrial matrix
where does the electron transport chain occur?
inner membrane of mitochondria (cristae)
how many ATPs are produced during the electron transport chain?
32-34
what is the role of oxygen in the electron transport chain?
final electron acceptor- joins with H to form water
direct contact cell signaling
May exchange signals through gap junctions or plasmodesmata
Cell-cell recognition. Membrane proteins of neighboring cells contact
paracrine signaling
secreted molecules diffuse locally and trigger a response in neighboring cells
synaptic signaling
a nerve cell releases neurotransmitter molecules into a synapse, stimulating the target cell
long-distance signaling
endocrine signaling- hormones released into circulatory system
reception (cell signaling)
ligand binds to receptor
transduction (cell signaling)
conversion of an extracellular signal to an intracellular signal in a signal transduction pathway that is amplified and relayed by second messengers
response (cell signaling)
the transduced signal triggers a specific response in the target cell
extracellular receptors
are NOT LIPID soluable and are unable to penetrate a plasma membrane, instead bind to receptor proteins at the OUTER surface of the plasma membrane (extracellular receptors) EX: GPCRs, ligand gated ion channels
intracellular receptors
receptors located inside the cell rather than on its cell membrane; hydrophobic Ex. steroids, hormones, nitric oxide
why do second messengers do?
relay the message and amplify the signal (cyclic AMP)
what responses can a cell have to a signal?
Trigger a protein that can alter membrane permeability, trigger an enzyme that will change a metabolic process, or trigger a protein that turns genes on or off
G1
Cell growth
S
DNA replication
G2
Cell prepares to divide
prophase
chromatin condenses, nucleoli disappear, duplicated chromosomes appear as sister chromatids, spindle begins to form, centrosomes move away from each other
prometaphase
nuclear envelope fragments, spindle enters nuclear area and some attach to kinetochores
metaphase
centrosomes are at opposite poles, chromosomes line up in middle, microtubules are attached to each kinetochore
anaphase
sister chromatids separate and move to opposite ends of the cell due to shortening of microtubules, cell elongates
telophase
two daughter nuclei form, nucleoli reappear, chromosomes become less condensed
cytokinesis
division of cytoplasm- animals cells- cleavage furrow, plant cells- cell plate
end result of mitosis
2 identical daughter cells (diploid)
what happens if a cell does not pass the G1 checkpoint?
it will enter G0
What happens if a cell does not pass the G2 checkpoing?
will try to repair and if not trigger apoptosis
What happens to levels of CDKs and cyclins during the cell cycle?
CDKs remain constant and cyclins fluctuate
What happens when a cyclin binds to a CDK
It becomes an active CDK complex which phosphorylates target proteins which help regulate key events in the cell cycle
contrast mitosis and meiosis
Mitosis produces 2 cells identical to the original cell. Meiosis produces 4 cells that are genetically different than the original cell.
Mitosis -diploid, meiosis- haploid
Mitosis produces somatic cells. Meiosis produces gametes or sex cells.
Mitosis- 1 division, Meiosis- 2 division
If an egg cell has 20 chromosomes, how many would the somatic cell have?
40
diploid =24. what is the haploid number
12
Prophase 1 of meiosis
synapsis (tetrad formation) and crossing over occurs
