cell bio unit 1

chs 1, 2, 3, 13, 14, 4, 16

building blocks of all living tissues

cells

how are cells generated?

from pre-existing cells

where do cells get their characteristics?

inherit from their predecessor cell

central dogma

DNA → RNA → protein

are viruses living?

no because they require a host to replicate; “molecular parasites”

what kind of genetic material do viruses have?

varies, can have:

• DNA

• RNA

• double-stranded

• single-stranded

“our _____ hold the code, but its their _____ that determines function”

1. genes

2. expression

what unit are cells measures in?

micrometers (μm)

light microscope characteristics (4)

• use light

• contain optics

• living cells glow under this

• units of measurement: ~50 μm

confocal microscope characteristics (4)

• uses a laser

• only used 1 wavelength of light

• florissant dye used to highlight specific proteins

• units of measurement: ~10 μm

electron microscope characteristics (2)

• units of measurement: nm (smaller than μm)

• allow u to see organelles of the cell

prokaryote characteristics (5)

• small + simple + single celled

• most diverse of all cells

• can adapt to extreme environments

• domains: bacteria, archea

• many different sources of “food” (O2, H, S, photosynthesis)

eukaryote characteristics

• bigger + elaborate organisms

• can be single or multi cellular

• have membrane-bound organelles

• have nucleus

why are some organelles membrane-bound?

allows for division of areas

nickname: plasma membrane

fence

nickname: nucleus

government

nickname: ribosomes

factories

nickname: mitochondria

power plant

nickname: chloroplasts

solar power plant

nickname: endoplasmic reticulum

highway

nickname: golgi body

post office

nickname: lysosome

waste disposal system

nickname: peroxisomes

chemical plant

nickname: cytoskeleton

cell scaffolding

function: plasma membrane

to separate / act as a barrier

function: nucleus

• holds DNA

• manages cellular activities

function: nuclear membrane

keeps DNA safe inside the nucleus

function: ribosomes

translate RNA to proteins

function: mitochondria

oxidate food mlcls to generate ATP

_____ contain their own DNA and reproduce themselves (like bacteria)

mitochondria

how did mitochondria evolve?

• from bacteria

• was ingested by a eukaryote and became a part of the eukaryotic cell since

what did eukaryotes likely evolve as?

predators

what is the most abundant organelle?

mitochondria

function: endoplasmic reticulum

moves proteins around

rough endoplasmic reticulum (RER)

ribosome-coated ER with makes proteins to be secreted

smooth endoplasmic reticulum (SER)

involved in lipid synthesis

function: golgi body

sorts proteins for final delivery destiny

function: lysosomes

intracellular degradation:

• break down food + release back to cell

• break down waste for recycling or excretions

function: peroxisomes

• chemical break down

• H2O2 (peroxide) generated + degraded inside

function: cytoskeleton

• physical strength

• scaffolding

• allow for cellular movement

• import by endocytosis; export by exosytosis

function: chloroplasts

photosynthesis

_____ have both mitochondria + chloroplasts

plants

rules of the cell

1. continually exchanging environment

2. not a closed system

3. central dogma: DNA → RNA → protein

Escherichia coli

• E. coli

• most thoroughly understood organism

• prokaryote

• genome is fully mapped

• single, circular double strand of DNA; ~4.6 million nucleotide pairs long

• produces 4300 diff kinds of proteins

Saccharomyces cerevisiae

• yeast

• minimal model eukaryote

• single celled

Arabidopsis thaliana

• common wall crest

• go through generations quickly: prods thousands of offspring in 8 - 10 weeks

• easy to grow indoors

• complete DNA sequence is known

Drosophila melanogaster

• fruit fly

• helped us understand genetics more than any other organism

• showed us how to trace case + effect from DNA instruction to structure of adult multicellular organism

Caenorhabditis elegans

• C elegans

• brain is completely mapped

• used in VCU alcohol studies

• all body cells are known (959)

• led to understanding of programmed cell death

• discoveries made involving fetal alcohol syndrome: showed alc at any does is unsafe; neurons don’t always die but they do misbehave

Danio rerio

• zebra fish

• transparent for 1st 2 weeks of life

• excellent for developmental studies

Mus musculus

• mouse

• helped us learn about Kit gene mutations (white stripe on forehead)

• social networks are comparable to humans

• many similarities to homosapiens while still being a lower mammal

Homo sapiens

• last step model organism for drug trial FDA clearance

• we are a model organism

primary cell culture

• isolated directly from live organism

• limited lifespan

• hayflick limit: the number of times a normal somatic, differentiated human cell population will divide before cell division stops

• normally functioning cells

immortalized cell line

• “transformed” cells

• can grow indefinitely like cancer

• unlimited uses: study cell behavior, response to drugs, and environment, industrial products

covalent bonds

• molecular marriage

• strongest bond

• electrons are shared

• determine shape of mlcls

ionic bonds

• valence electrons do bonding

• e- are giver or taken

• non-covalent → molecular dating

• close to the weakest bond

• cation: (+)

• anion: (-)

hydrogen bonding

• i.e. water

• weak bond

• non-covalent → covalent dating

atom

smallest particle of an element that retain distinctive chemical properties

atom parts

• nucleus: dense positively charged; contains protons + neutrons

• electrons

atomic / molecular weight

number of protons + neutrons

_____ determine how atoms interact

electrons

electrostatic attraction

attractive force occurring between oppositely charged atoms

polymerization

joining monomers into a polymer

polysaccharides

• monomer: monosaccharides

• joined by the covalent glycosidic bond

• 100s - 1000s of monomers

• i.e. glycogen

glycosidic bond

• created by the condensation reaction (mlcl of water is expelled as bond forms)

• broken by hydrolysis (mlcl of water is consumed)

lipids

• monomer: fatty acids

• parts

  • carboxyl group

    • chemically reactive

    • behaves as an acid

    • hydrophilic head

  • long hydrocarbon chain

    • not chemically reactive

    • hydrophobic tails

lipids: saturated

• no DB

• only single bonds

  • makes mlcl flexible

  • means solid @ room temp

• pack together in solid mass

  • think clogged artery

  • bad for health

• found in meats, dairies, and coconut oil

lipids: unsaturated

• contain at least one DB

  • means very rigid structure

  • rigid structure causes kinks

  • means liquid @ room temperature (DB / kinks prevent tight packing)

  • types

    • monounsaturated (1 DB)

    • polyunsaturated (multiple DBs)

proteins

• monomer: amino acids

• parts

  • carboxylic acid group → C terminus

  • amino group → N terminus

  • side chain → R group

  • hydrogen

  • a-carbon: links tg all parts

peptide bond

• covalent linkage bn adjacent AAs in protein chain

• formed through condensation reaction (water mlcl expelled)

nucleotides

• monomer: nucleic acids

• connected by phosphodiester bond

• 5’ → 3’

RNA

• ribonucleic acid

• bases: A + U, G + C

• usually (but not always) single stranded

DNA

• deoxyribonucleic acid

• bases: A + T, G + C

• only 1 hydroxyl group (think deoxy so 1 oxy is gone)

• double stranded

how are macromlcls linked?

covalent bonds

catabolism

• breaking down mlcls

• big → small

• useful form of energy

• small mlcls needed as building blocks

anabolism

• building up mlcls

• small → big

• uses energy generated by catabolism for the synthesis of mlcls that form the cell

2nd law of thermodynamics

the degree of disorder (entropy) can only increase in the universe

1st law of thermodynamics

energy can be converted to other forms but CANNOT be created nor destroyed

photosynthesis

• converts electromagnetic energy (sunlight) into chemical bond energy in cells

• light + CO₂ + H₂O → sugar + O₂ + heat energy

coupled rxns

• when two reactions work in tandem

• when u use the energy from a favorable rxn to carry out an unfavorable rxn

• require an energy carrier

phosphoanhydride bonds

• bonds in ATP / ADP

• high energy

• tough

• covalent

stepwise breakdown to create energy

• step 1: glycolysis

• step 1.5: pyruvate oxidized to acetyl coa

• step 2: citric acid cycle

• step 3: oxidative phosphorylation

glycolysis

• glucose → 2 pyruvate, 2 ATP, 2 NADH

• 2 ATP generated

• O₂ not needed but can be used

• happens in cytoplasm

when, where, and how is pyruvate oxidized to acetyl coa?

• when: after glycolysis (step 1.5)

• where: mitochondrial matrix

• how: via pyruvate dehydrogenase complex (large multi-enzyme complex)

what, other than pyruvate, can be converted to acetyl coa?

lipids

benefits of converting lipids to acetyl coa (as opposed to pyruvate with sugars)

• generate 6x as much energy as sugars per weight → so generate a lot of acetyl coa

• calorie dense

citric acid cycle

• acetyl coa → 1 GTP, 1 FADH_2, 2 CO_2, 3 NADH

• 1 GTP generated

• does NOT req O₂

• happens in mitochondrial matrix

oxidative phosphorylation

• O₂ → H₂O

• 30 ATP generated

• O₂ needed !

• occurs in the inner mitochondrial matrix membrane

gluconeogenesis

• reverse rxn of glycolysis

• steps 1, 3, 10 are irreversible

• takes a LOT of energy → makes you feel horrible

what type of cells would gluconeogenesis highly benefit?

brain cells → depend almost completely on glucose

glycogen

• multi-branched polysaccharide comprised of glucose

• acts as the primary, rapid-access energy reserve in animals

• balance of glycogen is regulated by hormones: insulin, glucagon, and adrenaline

glycogen phosphorylase

• enzyme that breaks glycogen

• condition used in: when no energy / food / sugar in system → want to break glycogen to release glucose into our systems

glycogen synthase

• enzyme that makes glycogen

• condition used in: when we have a lot of sugar in system → want to store excess energy

how is fat stored?

as droplets of water-insoluble triacylglycerols in specialized adipose tissue

what happens to excess sugar that’s intaken?

converted into fatty acids + stored

animals : glycogen → plants : _____

starch

how do plant cells store energy?

• starch: branched polymer of glucose (like glycogen)

• fat: like animals but unsaturated fatty acids predominate

how do mitochondria divide?

fission

what is it call when mitochondria join together?

fusion

what are mitochondria comparable to and why?

bacteria

• divide like bacteria → fission

• no nucleus nor organelles

• have circular copies of DNA

where in the cell might you find mitochondria?

where energy is needed

• i.e. cardiac tissue, neurons, sperm tails