cell phys exam 1

what can be seen under a microscope?

- Cell sizes

- Movement, shape changes, cell division

- Cell staining

- Cellular anatomy

light microscopy

- Magnification of up to 1000x

- Resolution of 0.2 um

- Often stained

- invented by Leeuwenhoek

- Robert Hooke first saw cells

fluorescent microscopy

- Staining cells with fluorescent dyes

- Filters isolate correct wavelength

confocal microscopy

- Similar to fluorescent but more specialized

- Uses a laser as a light source

- Results in a 2D image - optical section

- With computer integration - 3D image

transmission electron microscope

- Transmits beams of electrons

- Magnification of 1 million and resolution of 2 nm

- 2D image

scanning electron microscopy

- Coats the specimen with heavy metal

- 3D image

prokaryotic cells

- one celled organisms with no organelles (no nucleus)

- DNA in cytoplasm

- all have: cell membrane, ribosomes, circular DNA

- many have cell walls

- some have flagella, pili, capsules

- rod shaped, spherical, or spiral,

- small size but quickly responding

prokaryotic cell categories

- eubacteria

- archaea

eubacteria

everyday bacteria

archaea

live in extreme environments

- glaciers

- sulfur pits

- ocean depths

- cow stomachs

prokaryotic diversity

- Wide range of environments

- Variety of energy sources

- Can be photosynthetic

- Can live on/with us

eukaryotic cells

- single celled or multi celled organisms that have a nucleus

- have organelles

- much larger and more complex than prokaryotic cells

protozoans

single celled eukaryotes

nucleus

- Stores DNA

- Nuclear envelope

- DNA visible as chromosomes during cell division

mitochondria

- Cellular powerhouses that use cellular respiration to provide energy (ATP) for the cell

- Membraned organelles

- Contain their own DNA and divide like cells

chloroplasts

- Green organelles found only in plants and algae to make energy from sunlight

- Two membranes and stacks of chlorophyll

- Contain own DNA and divide like mitochondria

endoplasmic reticulum

- Enclosed by a folded membrane

- Cell membrane components and exported materials

golgi apparatus

- Stacks of flattened sacs

- Involved in chemically packing materials

- Many transport vesicles

lysosomes

- Site of intracellular digestion

- Breaks down food or waste

peroxysomes

- Vesicles that contain hydrogen peroxide reactions

- Inactivates toxic materials

vesicles

- Compartments for transporting between organelles

- Pinching off vesicles form one vesicle to fuse with another

- Endocytosis vs exocytosis

cytosol

- Cytoplasm without organelles

- More gel-like than fluid

- Site of chemical reactions

- Ribosomes (plentiful in cytosol)

cytoskeleton

- Filaments anchored to the plasma membrane or near nucleus

- Structural support and shape

- Manipulates internal and cellular movement

- Filaments (actin, microtubules, intermediate filaments)

properties of model organisms

- Reproduce quickly

- Genetically manipulated

- Genetic properties have been preserved

model organism examples

- E. coli

- yeast

- wallcress

- drosophila

- zebrafish

- mice

- humans

elements

substances that cannot be broken down or converted

atoms

smallest particles of an element

molecules

combinations of atoms

isotopes

- number of neutrons

- radioactive

ionic bonds

- transfer of electrons

- formed when only one or more electrons are required for stabilization

- weak, noncovalent bonds

- two charged ions form salts

covalent bonds

sharing of electrons

strength of bonds

covalent (strongest)

ionic

hydrogen (weakest)

single covalent bond

shares 2 electrons

double covalent bond

shares 4 electrons

polar covalent bonds

- electrons shared unequally

- link hydrogen and oxygen within a water molecule

- permanent dipoles

hydrogen bonds

- weak noncovalent bonds

- link water molecules together

- creating liquid water

hydrophilic molecules

polar bonds

dissolve easily in water

hydrophobic molecules

uncharged

do not mix well with water

acids

- release protons to become hydronium ion

- strong or weak

bases

- accept protons

- create OH- molecules

condensation reactions

making a bond by losing water

hydrolysis

breaking of a bond by adding water

four major families of molecules

sugars

fatty acids

amino acids

nucleotides

polysaccharides

what do sugars build into?

fats, lipids, membranes

what do fatty acids build into?

proteins

what do amino acids build into?

nucleic acids

what do nucleotides build into?

monosaccharides

glucose

fructose

galactose

oligosaccharides

sucrose

maltose

lactose

sugar functions

- Energy - 90% carbs used for ATP production

- Storage (glycogen)

- Structural supports

- Cell membrane components

sugar digestion

- GI tract (starches and di's, blood stream)

- Liver converts galactose and fructose into glucose

- 95% of sugar circulating in blood is glucose

glucose transport

- diffusion

- facilitated diffusion

- phosphorylated

sugar structure

combine with covalent bonds to form larger carbohydrates

polysaccharides

starch

glycogen

fiber

starch

glucose polymer in plants

glycogen

glucose polymers in animals

fiber

indigestible

diffusion

blood to interstitial fluid

facilitated diffusion

- interstitial fluid to cells

- role of insulin

hexokinase

most cells

irreversible

glucokinase

reversible in liver, kidney tubules, and intestinal epithelium

fatty acid structure

long hydrocarbon tail

hydrophilic head

classification of lipids

neural fats (triglycerides)

phospholipids

sterols (cholesterol)

amphipathic molecules

hydrophilic head and hydrophobic tail

fatty acid functions

- Concentrated food reserve (triacylglycerol)

- Steroids/hormones (communication)

- Cell membranes (phospholipids)

transport of lipids

- triglycerides

- absorbed through GI tract epithelium

- enter lymph and form chylomicrons

- passing into tissues

triglycerides

digested into fatty acids and monoglycerides

lipoproteins

lipid-containing droplets to shuttle fats

amino acid structure

amino group

carboxyl group

central carbon

side chain (r)

- forms proteins when combined

- polypeptides with covalent peptide bonds

nucleotide structure

5 carbon sugar with N ring

phosphate group

purines

pyrimidines

purines

adenine

guanine

pyrimidines

cytosine

uracil/thymine

nucleotide functions

energy (ATP)

information (DNA/RNA)

noncovalent bond types

ionic bonds

hydrogen bonds

van der waals attractions

hydrophobic interactions

capillary membrane

- semi permeable membrane

- between plasma membrane and interstitial fluid compartments

cell membrane

- selective barrier

- between interstitial fluid and intracellular fluid

protein structure

- long chain of covalently linked amino acids

- different amino acid side chains

hydrophobic forces

- Push hydrophobic molecules together

- Arranges proteins into compact conformations

protein shape

- easiest shape to form (least energy required)

- denaturing and renaturing

- size varies

types of protein shapes

globular

fibrous

sheets

rings

spheres

determining protein shape

x-ray crystallography

NMR

threading

chaperones

- help to fold protein correctly

- not to wrong proteins

- not to themselves (aggregates)

improperly folded proteins

Alzheimer's

Huntington's

Creuzfeldt-Jakob disease

prion

- abnormally shaped protein

- causes disease

alpha helix

- polypeptide chain twists into spiral

- hydrogen bond formation

- cell membranes

- coiled cell (2 twist)

beta sheet

- hydrogen bonds form between peptides that are laying side by side

- parallel vs anti-parallel

levels of protein organization

primary

secondary

tertiary

quaternary

primary protein structure

amino acid sequence

secondary protein structure

alpha helices and beta sheets

tertiary protein structure

polypeptide with alpha helices, beta sheets, and random coils

quaternary protein structure

more than one polypeptide chain

unstructured sequences

bend, flex, wrap around larger target proteins

flexible tethers

- provide movement and flexibility

- help scaffold proteins bring proteins together in intracellular signaling pathways

- assist elastin in forming rubberlike fibers

protein families

groups of proteins with similar amino acid sequences and conformations

unstructured protein regions

- larger proteins with numerous domains connected by polypeptide chains

- intrinsically disordered sequences

- targets for proteases

proteins as filaments, sheets, or spheres

- larger proteins dependent on complementary binding sites

- indefinite number of bindings

- actin

elongated fibrous proteins

- span long distances

- keratin filaments

- ECM

- collagen

- elastin

covalent cross-linkages

strengthen proteins by formation of disulfide bonds

protein binding

- proteins interact with ligands at binding site

- weak or strong binding (very specific)

- complementary binding with noncovalent bonds

disulfide bonds

- provides strength not structure

- also known as a disulfide bridge

- covalent bond derived from two thiol groups

- made to stabilize tertiary and quandary protein groups