BIO Final Flashcards
what are the parts of the scientific method?
observe question/problem hypothesis experiment conclusion
Controls and variables in experiment
Variable
- a factor that influences a process
- the variable may be altered in an experiment to see its effect on the outcome Control
- the variable is not altered
- allows for comparison between the altered variable test and the unaltered variable test
structure of membranes
- phospholipidsarranged in a bilayer
- globular proteins inserted in the lipid bilayer
- fluid mosaic model- mosaic of proteins floats in or on the fluid lipid bilayer like boats on a pond. (tight junctions restrict this)
4 components of cellular membranes
- phospholipid bilayer
- transmembrane proteins
- interior protein network
- cell surface markers
phospholipid bilayer
- double layer of phospholipids that forms in water, with hydrophilic parts facing outwards and hydrophobic tails facing inwards
- glycerol- 3 carbon polyalcohol
- 2 fatty acids (inwards)
- phosphate group (outwards)
transmembrane proteins
- transporters
- enzymes
- cell-surface receptors
- cell-surface identity markers
- cell-to-cell adhesion proteins
- attachments to the cytoskeleton
Membrane pores
extensive nonpolar regions within a transmembrane protein, can create a pore through the membrane (beta barrel) with polar interior
Ion channels
hydrophilic when open, allows passage of ions. Open or close from a chemical or electrical stimulus
carrier proteins
helps transport both ions and other solutes, such as some sugars and amino acids. Requires a concentration gradient.
covalent bonds
- when atoms share 2 or more valence electrons
- results in no net charge, satisfies octet rule, no unpaired electrons
- strength of bond depends on the # of shared electrons
- can be more than one atom sharing
ionic bonds
- donation of an electron
* formed by the attraction of oppositely charged ions
hydrogen bonds
- individual bonds are weak
- caused by cohesion or adhesion
- can be formed b/w 2 polar covalent water molecules or a water molecule and a polar organic molecule
cohesion
allows molecule to be attracted to another of the same type
adhesion
allows molecule to be attracted to another of a different type
atomic number
number of protons
atomic mass
sum of protons and neutrons. Protons = electrons
Isotopes
Atoms of one element that vary only in the number of neutrons in the nucleus
pH: Acid
- 1-7
- any hydrophobic (non polar) substance that increases hydrogen
- the stronger the acid the more hydrogen and the lower the pH
pH: Base
- 7-14
- hydrophillic (polar)
- lowers the hydrogen
hydrolysis
breakdown of large molec. with the addition of water
dehydration synthesis
formation of large molecules by removal of water
structural components of amino acids
- primary
- secondary
- tertiary
- quaternary
primary structure
sequence of amino acids fastened together by peptide bonds
secondary structure
interaction of groups in the peptide backbone: alfa helix and beta sheet
tertiary structure
final folded shape of a globular protein. stabilized by number of forces. final level of structure for proteins consisting of only a single polypeptide chain. 3D shape
quaternary structure
arrangement of individual chains in a protein with 2 or more polypeptide chains interacting with eachother
structural components on nucleic acids
- nucleotides
- 5 carbon sugar+phosphate+nitrogenous base
- nucleotides connected by phosphodiester bonds
purines
adenine and guanine
pyrimidines
thymine and cytosine, and uracil
Basic building blocks of cells (4)
- Proteins (polymers of amino acids)
- Nucleic Acids (polymers of nucleotides)
- Polysaccharides (polymers of sugars)
- Lipids (polymers of hydrocarbons)
types of organelles: eukaryotic
nucleus, ribosomes, endomembrane system, ER, Golgi apparatus, lysosomes, microbodies, vacuoles, mitochondria, chloroplasts, cytoskeleton, centrosomes, ECM
Nucleus
- holds genetic info
* nucelolus- where rRNA synthesis takes place
ribosomes
- protein synthesis machinery
- links amino acids together through dehydration synthesis, forming peptide bonds and finally proteins
- rRNA protein complex
- may be free in cytoplasm or associated with internal membranes
Endomembrane system
divides cell into compartments
ER
- Rough- attachment of many ribosomes. Synthesis of proteins to be secreted, sent to lysosome or membrane
- smooth- few ribosomes. Synthesis, store calcium, and detox
Golgi apparatus
- flattened stacks of interconnected membranes
- packaging and distribution of molec. which vesicles then transport
- cis-face nucleus
- trans- faces plasma membrane
- produces glycoprotiens
lysosomes
- membrane bound digestive vesicles
- arise from GA
- enzymes catalyze breakdown of molec.
- phagocytosis: destroy foreign matter
microbodies
peroxisomes- vesicles that contain enzymes involved in oxidation of fatty acids
vacuoles
- in plants
- central- storage (starch)
- contractile- protists, pumps out water
- storage
mitochondria
- powerhouse of cell
- has own membrane
- has own DNA
- oxidative metabolism
cholorplasts
- in plants
- contains chlorophyll
- thylakoid membrane- sacs within the membrane
- grana- stacks of thylakoid membrane
cytoskeleton
- network of protein fibers found in eukaryotes. supports shape and keeps organelles fixed.
- microfilaments- (actin) contraction
- microtubules- largest, facilitate movement in cell
- intermediate filaments- stability
centrosomes
region surrounding centrioles
ECM
protein and other materials outside the plasma membrane that cell secretes out. forms protective layer.
prokayotic DNA
circular, only one origin of replication
eukaryotic DNA
linear, many origins of replication
prokaryotic cell
simple structure, nucleoid, small ribosomes, fission, small, simple flagella
eukaryotic cells
complex, nucleus, chromatin, large ribosomes, membrane bound organelles, large, complex flagella