Bio 113- Unit 1

Features of evaluation of a claim

• evidence- quantitative info (numbers)

• source- scientific study that has been published in peer review journal

• mechanism- scientific explanation for what is going on

why is the process of science reliable?

• self corrective (mistakes caught bc scientists scrutinize each other’s work)

• peer review

• conclusions always subject to change based on new evidence

• experiments are designed to disprove hypothesis

• objective hypothesis testing

belief perseverance

tendency to cling to a belief even if evidence supports the contrary

hypothesis

what they hypothesize is happening

• significant difference

null hypothesis

what they hypothesize is not happening

• no significant difference

prediction

what we expect to measure if the hypothesis is correct

• the null is rejected

• dosage, duration, and measurement

testing the hypothesis

• null is rejected if prediction is correct

• null fails to be rejected if prediction is incorrect

experimental group

• receives the experimental treatment

negative control group

• has the same conditions as the experimental group except for the experimental treatment

scientific consensus

When multiple scientists test their predictions using experiments, and they all agree with one another

sample size that will provide the most accurate mean

• little variation (we want this!)= bigger sample size

• we take a subset of the population that will be reflective of the population

sample

subset of the population that has been measured

standard deviation

how close the majority of the population sits to the mean

• measure of the variation of the sample

what curve will have the smallest standard deviation

• narrow curve= less variation in measurements (this is what you want)

standard error

• tells us about how the standard deviation relates to sample size

• we want standard error to be low

statistically significant

• significant difference (wasn’t due to chance)

• *= indicates statistically significant difference

• the more * you see on a graph= the more confident you can be that the difference is truly significantly statistically different

• reject the null hypothesis

scientific theory

• a hypothesis that describes a widespread phenomenon in nature that has been tested many times and in those times the null was rejected

cell theory

all living things are made up of cells

chromosome theory of inheritance

• dna is the heritable material that gets passed from parent to offspring

the theory of evolution

• the population of organisms change over time

• most controversial

natural selection

the process by which species change over time

• occurs when individuals within a population vary in characteristics that are heritable

• in a particular environment, certain versions of these heritable characteristics help individuals survive and reproduce more often than others

where does variation come from in natural selection

• mutations

• random mistakes in DNA replication

• arise by chance

• the more something replicates/reproduces, the more mutations/variation is generated

understanding evolution by natural selection is critical for medicine

• antibiotic resistance bacteria

atoms

• nucleus in center

• electrons move around the nucleus in orbitals

• orbitals are grouped into levels called electron shells

valence shell

• the outer shell

• atom is most stable when its valence shell is filled

nonpolar covalent bond

• equal sharing of valence electrons between atoms in a covalent bond

polar covalent bonds

• unequal sharing of electrons between atoms in a covalent bond

• ex/ water

• unequal charge

electronegativity

• strength at which an atom’s nucleus pulls electrons

Macromolecule

lipids

• consist of C-H bonds

• nonpolar

Macromolecule

Carb

• consist of C=O groups bonded to -OH groups with some C-H bonds

• polar

• ex/glucose

Macromolecule

Nucleic acids

• consist of nucleotides; phosphate group, sugar, nitrogenous base

• polar

which macromolecules will dissolve in water

• carbs and nucleic acids bc they are polar

phospholipids

• lipids that make up the cell membrane

• have a nonpolar region (the tail) and a polar region (the head)

• form lipid bilayers in water

• cell membrane (lipid bilayer): hydrophilic heads interact with each other, with water, and with other polar molecules- hydrophobic tails don’t interact with anything

which molecules would get through cell membrane on own

• non polar and small molecules bc not attracted to polar heads

• O2, CO2, N2

• H2O: small and polar: wont get through on its own usually bc it will interact with polar head, but a very small amount can due to small size

• glucose/sucrose: large and polar (can never get through on it’s own)

• Ions: can’t get through on own bc of their charge but they are small

saturated lipid

hydrocarbon chains consist of only single bonds between carbons

• long

unsaturated lipid

hydrocarbon chains have one or more double bonds

• short

• has curves

• greater permeability

decreased temp and effect on lipid movement

• slows lipid movement= hydrophobic tails in center to pack closer together

• at very low temps= lipid bilayers solidify

Would you expect a fly that lives in Antarctica to have more saturated or unsaturated phospholipids in their cell membranes compared to a fly that lives in the hot desert?

• fly that lives in arctic would have more unsaturated phospholipids

• cold temps= decrease permeability

• there needs to be more unsaturated lipids to increase permeability

cystic fibrosis

• disease caused by a defect of membrane transport

• genetic disease

• primary symptom: mucus is think and sticky (blocks airways and interferes with digestion and absorption)

• causes very early death

• people with CF= genetic mutation which makes the chloride protein channel nonfunctional (Cl- can’t move from inside the cell to outside of the cell)

why does Cl- need a protein channel to get through cell membrane?

• Cl- is an ion= can’t get through cell membrane on own

• gets stuck to polar heads

diffusion

• solutes move from high concentration to low concentration until equilibrium is reached

• the cell membrane must be permeable to that solute

osmosis

• water moves from low solute concentration to high solute concentration until equilibrium is reached

• there must be a concentration difference for water to move

is there a connection between diffusion and osmosis?

yes

• Concentration of Ca in a cell is higher inside than outside the cell, the cell

  pumps Ca from inside the cell to outside the cell, now there is more Ca outside

  the cell.

• the water moves from inside to outside because water will move towards the higher solute concentration. Water always follows solutes.

outside solution is hypertonic to the inside

• hyper= more

• Higher solute concentration outside the cell than inside you can say the outside is hypertonic compared to the inside

• cell will shrink

• water moves from inside to outside

outside solution is hypotonic to the inside

• hypo= less

• if there is a higher solute concentration inside the cell than outside, the outside is hypotonic compared to the inside

• water moves from outside to inside

• cell expands and bursts

isotonic

• outside and inside solute concentration are equal

• no change in the cell

simple diffusion

diffuse directly through the cell membrane down their concentration gradient (from high to low)

facilitated diffusion

uses a protein channel to diffuse through the cell membrane down concentration gradient (high to low)

• doesn’t require energy

active transport

move through cell membrane against their concentration gradient (low to high) through protein channel

• uses energy

primary active transport

protein pump moves ions against their concentration gradient

• ATP is used

secondary active transport

• uses electrochemical energy

• in the same cotransporter

what are proteins made of?

• amino acids (building blocks)

primary structure

• sequence of animo acids

secondary structure

• spirals or folds

• alpha-helix or beta-pleated sheets

tertiary structure

• complex 3D shape

• gives the protein the function

quaternary structure

• not a real structure

• multiple tertiary structures forming one complex

what is an enzyme

• tertiary proteins

• speed up rate of chemical reactions

• work by acting as catalysts

• destabilize bonds in substrates (reactants) and lower the activation energy required for a reaction to start

active site

reactants enter and products leave

induced fit

the substrate induces a slight change in shape of the enzyme so that it can fit perfectly

allosteric inhibition

when a regulatory molecule binds somewhere other than the active site

competitive inhibition

• reversible

inhibitor molecule directly binds on the active site

• reversible

• only returns to 100% of its function in competition

reversible

adding a phosphate group to inactivate (or activate) the enzyme

• increasing reactant concentration

irreversible

• peptide bond is cut

metabolic pathway

• a specific molecule is altered in a series of steps that results in a final product