BIO SL

theory vs law

theory explains, law states

cell theory

1. all living things are made of cells

2. cell = most basic unit of life

3. all cells come from pre-existing cells

exceptions to cell theory

• skeletal muscle fibres — long cells, many nuclei

• giant algae — relatively big (10 cm) but only one nucleus

7 functions of life

• metabolism

• response

• homeostasis

• growth

• reproduction

• nutrition

• excretion

are viruses alive?

everybody say it with me now! NO.

do antibiotics work on viruses (like the flu?)

again, all together now! NO.

strengths of electron microscopes

• increased resolution

• increased magnification

limitations of electron microscopes

• can’t view living organisms

• no colour

explain SA:V ratio and its importance

• larger ratio is preferred (large surface area, small volume)

• helps with efficiency

• that’s why cells divide before they get too big (small volume)

• flattened/elongated shape (e.g. bacillus)

• large central vacuole = less volume (only plant cells)

• folds = more surface area (e.g. mitochondria)

• villi = more surface area (e.g. small intestine)

emergent properties

cells work together to perform life functions

cell differentiation

different cells = different functions, even with the same DNA (gene expression)

stem cells and their benefits

cells that have yet to differentiate (in embryos)

• can reproduce many times

• can turn into any kind of cell

example of stem cells use for treatment

leukemia, stem cells can be introduced to produce red & white blood cells

components of prokaryotes

• plasmid

• capsule (for attachment to other organisms)

• plasma membrane

• nucleoid (contains genophore)

• cell wall

• 70S ribosomes

• flagella

plasmid

circular DNA that can be transferred between bacteria

flagella

tails at the ends of some cells (e.g. bacteria, sperm) to aid with locomotion

genophore

bacterial “chromosome” (i.e. DNA)

how do bacteria reproduce/divide

binary fission

components of (eukaryotic) animal cells

• nucleus

• nucleolus

• rough ER

• smooth ER

• mitochondria

• peroxisome

• golgi apparatus

• cell membrane

• 80S ribosomes

• cytoskeleton

nucleus function

holds DNA

nucleolus function

rough ER function

smooth ER function

mitochondria function

cellular respiration/ATP production

peroxisome function

golgi apparatus function

cell membrane function & structure

• phospholipid bilayer, embedded proteins, cholesterol

• hydrophobic lipid tails on the inside

• hydrophilic heads on the outside (bc cell is aqueous)

• semipermeable

• decides what goes in and out of the cell

ribosome function

catalyze the formation of polypeptides

cytoskeleton function

differences between plant and animal cells

Plants have:

• chloroplasts

• cell wall made of cellulose

• large central vacuole

• no centrioles

• no cholesterol (in cell membrane of animals)

cholesterol in cell membranes

• steroid

• hydrophobic w/ a hydrophilic end (so it fits in the membrane)

• maintains membrane fluidity, stability, and permeability

  • plants use saturated & unsaturated fatty acids instead

• cells can work in a larger temp range

integral proteins

penetrate ;) the membrane

peripheral proteins

attached to the membrane

what is able cross the membrane?

• hydrocarbons

• oxygen

• small, uncharged, polar molecules

what can’t cross the membrane (w/o proteins)

• ions

• large molecules

passive transport

• high to low (solute) concentration

• requires no energy

• includes simple and facilitated diffusion (and osmosis)

active transport

• low to high (solute) concentration

• requires energy

hypertonic solution (OUTSIDE the cell)

• higher concentration (OUTSIDE the cell)

• water rushes out

• animal cells shrivel (and die)

• plant cells plasmolyze (and die)

hypotonic solution (OUTSIDE the cell)

• lower concentration (OUTSIDE the cell)

• water rushes in

• animal cells lyse/burst (and die)

• plant cells become turgid (no death bc cell wall yippee!)

isotonic solution (OUTSIDE the cell)

• equal concentration

• no net change

• no death!

simple diffusion

just go through the cell membrane

facilitated diffusion

still no energy but need protein channels

exocytosis

cell secretes macromolecules by fusing vesicles w/ the membrane

• neurotransmitters

• secretion of insulin by pancreas

endocytosis

cells take in substances

• phagocytosis (take in food (ph = f = food))

endosymbiosis theory

long ago a prokaryote engulfed another smaller one and it became a eukaryote

evidence for endosymbiosis

mitochondria and chloroplasts were likely once prokaryotes, because they:

• have double membranes

• divide through binary fission

• have their own DNA

• have their own ribosomes

phases of interphase

• G1

• S

• G2

• G0 (sometimes)

G = gap; S = synthesis

Gap 1 of Interphase

normal function & growth

Synthesis of Interphase

DNA replication for mitosis

Gap 2 of Interphase

preparation for mitosis

Gap 0

non-dividing phase (G1 to G0)

e.g.neurons don’t replicate

phases of mitosis

prophase, metaphase, anaphase, telophase, cytokinesis

cytokinesis in animals

cell membrane pinches (cleavage furrow)

cytokinesis in plants

can’t pinch because of cell wall

vesicles move to the cell equator and become cell membrane, then more vesicles bring materials to build cell wall

which proteins regulate the cell cycle?

cyclins

what is metabolism?

all of the chemical reactions that occur in a cell

anabolism

synthesis of complex molecules from simpler ones (e.g. condensation/dehydration synthesis reactions)

catabolism

breakdown of complex molecules into simpler ones (e.g. hydrolysis)

what are the 4 macromolecules

carbohydrates, lipids, proteins and nucleic acids

disaccharides to know

• maltose

• sucrose

• lactose

polysaccharides to know

• cellulose (cell walls)

• starch (store glucose/energy in plants)

• glycogen (store glucose in animals)

saturated vs unsaturated fatty acids

saturated = all single bonds, solid at room temp, straight molecule

unsaturated = 1+ double bond, liquid at room temp, bent molecule

trans fats

when hydrogens are added to unsaturated fats (double bonds) and they’re on opposite sides of the chain

lipids vs carbs for energy storage

lipids are for long term energy storage, hold twice as much energy

carbs are for short term energy storage

how many amino acids are there?

20

which part of the amino acid differentiates it?

the R group

7 functions of proteins

1. structure (e.g. collagen or spider silk)

2. regulation (hormones, e.g. insulin)

3. immune defense (e.g. immunoglobulin)

4. transport

5. signal transduction receptors

6. movement

7. enzymes

proteins vs polypeptides

it’s a protein is it’s capable of function

proteome

specific set of genes coded by an organism’s DNA (essentially a protein genome)

what are enzymes?

proteins that catalyze reactions (reduce the energy required for a reaction)

activation energy

minimum energy required to begin a reaction

enzyme-substrate specificity

each enzyme only has one substrate

factors of enzyme activity

• temperature

• pH

• substrate concentration

what kind of macromolecule is ATP

nucleic acid (CHONP)

what are the 2 steps of protein synthesis

transcription & translation

transcription

DNA → mRNA

translation

mRNA → amino acids (via tRNA)

why does DNA need to be transcribed to RNA for protein synthesis

DNA can’t leave the nucleus

which enzyme unzips DNA for protein synthesis

RNA polymerase

is the entire DNA unzipped for protein synthesis?

no, just that specific gene

codon

set of 3 mRNA bases that “codes” for an amino acid

anticodon

complimentary 3 bases in tRNA that match the codon and bring over the amino acid

what does rRNA do?

makes up ribosomes (location for protein synthesis)

what is the start codon?

AUG (on mRNA), codes for methionine

gene

a section of DNA that codes for a specific characteristic

allele

variations of a gene

e.g. if the gene is eye colour, alleles are blue eyes, brown eyes, green eyes, etc.

locus

the location of a gene on a chromosome

haploid (n)

one set of chromosomes (sex cells/gametes)

diploid (2n)

two sets of chromosomes (autosomal/body cells)

advantage of diploid cells

harmful recessive alleles can be masked by dominant ones

key differences in the phases of meiosis

meiosis I

• reduction division (diploid → haploid)

• homologous chromosomes separate

• crossing over occurs

meiosis II

• mitotic division (haploid → haploid)

• sister chromatids separate

nondisjunction

homologous chromosomes don’t separate during anaphase I, resulting in sex cells with an incorrect amount of chromosomes

cystic fibrosis is a…

autosomal recessive disease

Huntington’s disease is a…

autosomal dominant disease

sex-linked (X-linked) diseases to know

• red-green colourblindness

• hemophilia

who is more likely to have X-linked diseases

males (women can be carriers, men can’t)

gel electrophoresis

separates either proteins or DNA on the basis of size and electrical charge

• DNA profiling

• DNA fingerprinting

PCR

amplifies DNA

• forensic analysis

• detect viruses like HIV

• detect genetic disorders

• DNA profiling

autotroph