DP1 Biology

Habitability Boundary

carbon molecules from meteorites began forming oceans

prebiotic atmosphere characteristics

no O2, more CO2, N2, H2O

modern atmosphere

ozone layer to keep O2, less CO2, similar N2/CH4 as prebiotic

characteristics of living things

movement, respiration, sensitivity, growth, excretion, reproduction, nutrition

cell theory

cells are the smallest unit of life, all living things are one or more cells, all cells come from pre-existing cells

simple organic compounds

carbon based (ex. carbon, oxygen, hydrogen)

miller-urey experiment

prebiotic atmosphere elements + lighting to start reaction —> more complex compounds

RNA world

theory that rna was first form of genetic material because it can self-replicate

spontaneous formation of membranes

formation of phospholipid bilayer

luca

last universal common ancestor:

• universal genetic code suggest

• hydrothermal vents provided ideal conditions (protection from sun, necessary minerals/molecules, “white smokers” create good temp, pockets that molded early cells)

prokaryotic cells

cell walls, plasma membrane, cytoplasm, circular dna, 70s ribosomes

eukaryotic cells

nucleus, mitochondria, golgi apparatus, endoplasmic reticulum, 80s ribosomes, cytoskeleton

conditional structures

• cell wall

• lysosomes

• vacuole

• chloroplasts

• centrioles

• flagella/cilia

light microscope

see things in color/living things but limited zoom. uses fluorescent stains, immunofluorescence

electron microscope

more zoom but no color/living things. uses freeze fracture/cryogenic electron microscopy

magnification

image/actual or size of scale bar/label of scale bar

VALUES MUST BE IN SAME UNIT

endosymbiosis

one bacteria engulfs the other — one lives inside the other and they both benefit

mitochondria existing independently?

may have because of own cell membrane and circular dna genome

virus structure

vary greatly but all

• small fixed size (no growth)

• nucleic acid genetic material

• capsid made of protein to protect genetic material

• no cytoplasm, few/no enzymes

lytic cycle

1. bacteriophage (virus) attaches to host cell surface and injects dna into host

2. phage dna replicates and makes proteins that assemble into phages

3. the cell lyses, releasing phages and cycle repeats

lysogenic cycle

1. virus attaches to host and its dna becomes incorporated into host genome

2. cell divides and dna from virus is passed on

3. under certain conditions lytic cycle will begin

obligate parasites

viruses all rely on host cells

origin of viruses hypotheses

1. regression hypothesis: one origin of viruses, “reductive evolution”

2. escaped genes hypothesis: multiple origins

rapid evolution of viruses examples

1. influenza virus: quick reproduction is prone to mistakes —> fast evolution

2. HIV: retrovirus — contains transcriptase which is enzyme that converts rna to dna that can be incorporated into host cell

biochemical fractionation

centrifugal force to separate cellular components based on density.

clathrins

proteins in golgi apparatus that specifically help with endocytosis

amphipathic

molecules that have both hydrophilic and hydrophobic regions

integral proteins

also amphipathic, cross the bilayer

peripheral proteins

only cross one layer of membrane

glycolipids

attached to directly to phospholipid, on the surface of membrane to help with cell recognition and signaling.

glycoproteins

attached to integral protein, on the surface of membrane to help with cell recognition and signaling.

fluid membrane

unsaturated hydrocarbon tails with bends, more fluidity

viscous membranes

saturated tails, can withstand high temps/more kinetic energy. more stability

cholesterols in plasma membrane

molecules that stabilize membrane structure and fluidity, reducing permeability and enhancing rigidity.

fluid mosaic models

another name for cell membranes

selective permeability of bilayer

small, non-polar molecules can cross

cell-adhesion molecules (cam)

used to make tissues by connecting cells

desmosomes

sturdy and flexible sheets of cells in organs to hold cells together when stretched. have channels to help with communication

plasmodesmata (plants)

tubes connecting cytoplasm of adjacent cells to allow for exchange of materials

water potential

higher at roots, decreases as you go up the tere. high solute in leaf —> low solute potential.

water moves TO LOW WATER POTENTIAL

turgor pressure

how cell walls maintain shape

solvent properties of water

universal solvent — polar and ionic substanes can dissolve

thermal properties/high specific heat capacity

water needs lots of energy to change temp which allows us to maintain homeostasis

buoyancy

upward force —> floating

viscosity

resistance to flow (eg. running on water vs. in air)

conductivity

ability to conduct heat (eg. body heat is lost in water)

goldilocks zone

water is essential for life; closer to sun it would evaporate and farther it would freeze

carbohydrates function

sugars, starches, fibers, that primarily provide energy

carbohydrate structure

made up of monosaccharides

• hexoses have 6 carbons

• pentoses have 5 carbons

condensation reaction or dehydration synthesis

anabolic reaction that forms water as a product

hydrolysis

catabolic reaction

carbon numbering

start from right-most, move clockwise

amylose

• found in plants

• continuous thread

• helix structure

• made up of alpha glucoses

• 1’ and 4’ bonds

amylopectin

• found in plants

• branching with 1’ and 6’ linkages

• made up of alpha glucoses

• 1’ and 4’ bonds

glycogen

• found in animals

• energy storage

• similar to amylopectin in structure

cellulose

• made of beta glucose

• form straight chains

• glucose alternates in orientation, forming hydrogen bonds

• humans cannot digest —> forms bulk to keep things moving through digestive system

ruminants

animals that can digest plant material because of their unique digestion process

lipids structure

• triglycerides are made up of glycerol and fatty acids

• don’t have repeating subunits/specific ratios like carbs, so they are not polymers

lipid formation

glycerol + fatty acid/hydrocarbon chain is a condensation reaction

energy storage in lipids

more long term and release 2x energy when metabolised

lipid solubility

nonpolar making them insoluble in water

saturated fatty acids

no double bonds —> highest melting point

monounsaturated fatty acids

only 1 double bond —> low melting point/liquid at room temp

polyunsaturated fatty acids

multiple double bonds —> low melting point/liquid at room temp

adipose tissue

cells in animals that store triglycerides

adipocytes have large vacuoles for storage and help insulate

photosynthesis equation

6H2O + 6CO2 —> C6H12O6 + 6O2

most of a plant’s mass?

most of a plant’s mass comes from air

pigments

how plants absorb light energy. common is chlorophyll a which absorbs reflects green, accessory pigments are for other colors

chromatography

highest on paper is most soluble

absorption spectra

amount of light energy absorbed at varying wavelengths for specific pigments

action spectra

photosynthetic activity for specific pigments

redox reactions