Glossary of BSC2010

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Robert Hooke
1665 First described a named cells
Loreza Oken
1805 " All life comes from cells and is made of cells"
Schleiden and Schwann
1839 credit for the cell theory
1855 All cellss come from pre-existing cells
Cell Theory
All org consist of 1 or more cell, cells are smallest unit of life and come from pre-existing cells, cells divide to form new cells
small 1-10 microns, usually have a cell wall, no membrane bound organelles, no nucleus, circular DNA concentrated in nucleoid region, plasma membrane, cytoplasm, ribosmes, some have capsule
membrane bound organelles, 10-100 microns, complex chromosomes, double nuclear membrane
Theory on origin of Eukaryotic and Endosymbiotic
invagination of cell membranes: mesosomes in modern-day bacteria

endosymbiotic theory: one prokaryote ate another, but didn't digest it; mitochondria and chloroplasts have own DNA and copy and divide w/o cell division, have double membrane
advantages of membrane-bound organelles
partitioned compartments allow simultaneous jobs, unique chemistry in each, participate in metabolic rxns, sequestered reactions,
plasma membrane
phospholipid bilayer with molecules floating in it
things that pass through plasma membrane easily
small non-polar - hydrocarbons, O2, CO2

small polar - uncharged molecules, H20
things that dont' pass through plasma membrane easily
large polar molecules
functions of membrane protein
channels - gates that open/close mainly for ion transport

receptors - mainl for hormones, hormones bind to receptors and usually trigger second receptors

carriers - pick up molecules and rotate them into the cells

cell-cell recognition - mostly for cell identification
microlattice of 3 fibers, can be taken apart and rebuilt

microtubules - tubulin
microfilaments - actin
intermediate filaments - keratin
plant cell differences
have cells walls - cellulose : nonliving, very permeable, secreted by cells

plastids : support and provide structure
1. site of oxidative metabolism, muscle cells have lots of mitochondria

2. enclosed in double membrane, result of ES Theory, inner membrane folded to increase SA, cristae - where metabolism occurs

3. have own DNA, mtDNA

4. mtDNA changes slowly over time, due to genetic drift, which is by chance.
function in protein synthesis

1. not membrane bound

2. takes mRNA and translate genetic code into AA, translation occurs in cytoplasm

3. subunits make in nucleoli, only assembled when making proteins
2 types of ribosomes
free ribosomes - makes protein that stays in the cytoplasm

bound ribosomes - make membrane proteins and secretory protein
"factory of cell"

1. thought to have come from invaginated cell membranes

2. membranous network encloses cisternal space

3. membrane is continuous w/ nuclear envelope ( outer membrane)
Rough ER
has ribosomes attached, makes protein, peptide hormones, secretory proteins, found in pancreas a lot
Smooth ER
no ribosome, produces polysaccharides and lipids, steroids, phospholipids, detoxifies poison - liver, stores Ca2+ -gonads
golgi body
"sorting and shipping center"

1. modifies ER products and produces biomolecules

2. receive molecules on the cis side

3. receives vesicles from ER on cis side
site of cellular digestion - basically a sack of hydrolytic enzymes

1. have diff't for breaking spec biomolecules

2. low pH ~5 pumping protons into lysosomes

3. fuse with food vacuoles for intracellular digestion

4. selectively destroy old cells' part

Tay-Sachs Disease - lacks lipase, caused by nonfunctional lysosomal enzyme, lipids accumulate in the brain
found in plant cells

1. double membrane

2. own DNA

3. mostly function in photosynthesis

4. contain pigments

5. storage - leucoplasts store starch
usually for storage, fluid filled membrane encloses, contractile vacuole: cell size, turgidity, storage in protists = water balance
passive transport
does not involve energy used by the cell; no ATP

1. Diffusion - temp affects rates, molecule size, and charge

2. osmosis - diffusion of water instead of molecules thought a semi-permeable membrane
facilitated diffusion
normal diffusion occurs through a transport channel, but protein does not change shape

channel and carrier proteins
active transport
1. requires cellular energy, ATP

2. uses carrier proteins to help ions cross membrane

3. usually pumps one out of the cell while pumping another in

4. usually used to keep substances needed in higher concentration inside of the cell than outside - trace elements
for large molecules
Exocytosis - export substances outside of the cell. vacuole fues w/ cell membrane, releases contents outside the cell

Endocytosis -

1. phagocytosis - cell eating pseudopodia engulf substances form a food vacuole. fuse w/ lysosome to digest contents

2. pinocytosis - droplets are taken in w/ vesicle formation

3. receptor-mediated endocytosis - specially transport
cell connections in plants
plasmodesmata - similar to gap junctions. cell membranes connected through pores in cell walls, allows walls to store molecules of communication
cell connections in animals
tight junctions - keep substances from substances from passing b/t cells; in order for something to move, must go through the cell; intestinal epithelia

desmosomes - cells form to make strong sheets of tissue

gap junctions - cells connected by protein rings. allows ions of small molecules to pas thorugh rapidly, cell-cell, ie. heart muscles
characteristics of animals
1. ingestive and heterotrophs

2. eukaryotic and multicellular

3. store carbs as glycogen

4. most hav enerve and muscle cells

5. generally sexual reproduction; diploid form is dominant
I Split
Parazoa - no true tissues - porifera ...sponges

Eumetozoa - true tissues
II Split
Within Eumetazoa
Radiata - jellyfish, round animals, radial symmetry; diploplastic - cnidaria and ctenophora

Bilateria - bilateral symmetry, triploplastic, leads to cephalization
III Split
Within Bilateria
Acoelomates - do not have a body cavity- platyhelminthes...flatworms

Pseudocoelomates - not completely lined, not capable of peristalsis,- nematoda and rotifera

Eucoelomates - true coelom, body cavity completely lined mesodermal origin...
IV Split
Within Eucoelomates
Protostomes - blastophore forms mouth, spiral cleavage, schizocoelous, annelida, mollusca, arthropoda

Deuterostomes - blastophore forms anus, enterocoelous, radial cleavage - Echinodermata, Chordata
I. Parazoa : Phylum Porifera
1. sessile
2. mostly marine
3. sac like body w/ pores ( where water goes in)
4. central cavity - spongocoel
5. large opening - osculum (where water goes out)
6. filter feeders use choanocytes
7. choanocytes move water, engulf food (phagocytosis), can make gonads
8. body wall is 2 cell layer thick - epidermis and choanocyte layer
9. amoebocytes in mesohyl makes gametes, secrete skeleton, digestion and circulation of nutrients
10. skeleton can be protein (spongin) or spicules (SiO2 or CaCO3)
11. hermaphroditic ie monecious
12. reproduce asexually - budding, fragmentation, regenerate very easily.
II. Eumetozoa :
A. Radiata
1. Phylum Cnidaria: Sea Anemones, jellyfish, corals

1. diploplastic
2. mostly marine
3. sac-like body w/ gastrovascular cavity only 1 opening = mouth
4. 2 body plans -
a. polyps - usually sessile, asexual
b. neduscae - floating, sexual

5. have tentacles - for feed/defense, stinging cells (cnidocytes)
6. no brain but generalized nerve net
II. Eumetazoa
A. Radiata
ii) ctenophora
the comb jellies :
1. triploplastic - true muscle, but biradial

2. exclusively marine

3. 8 comb rows of fused cilia ( locomotion)

4. 2 tentacles w/ sticky cells instead of stinging called colloblasts
II. Eumetazoa
A. Radiata
i) cnidaria
3 main classes :

a. hydrozoa - hydras, hydroids, portugeese-man-of-war. polyp dominant
b. scyphozoa - jellyfish. have both body plans
c. anthozoa - anemones and corals/. only polyps
II. Eumetazoa
B. Bilateria
Platyhelminthes: flatworms ( are Lophotrochozoans)

1. terrstrial, marine, aquatic
2. most a parasite. also free-living
3. no body cavity
4. dorsal-ventral flat
5. bilateral, unidirectional movement
6. moderate cephalization, ganglion in head
7. triploplastic
8. mouth, but no anus...incomplete digestive tract
II. Eumetazoa
B. Bilateria
a. phylum platyhelminthes
1. class turbellaria
turbellaria: planarians
1. free-living, terrestrial, aquatic, marine
2. no circulatory sys; only diffusion across membrane
3. excrete ammonia by diffusion, use protonephridia (flame cell) for water balance
4. move by ciliary gliding and muscular undulations/contraction
5. photosynthesis eye spot and chemosensory flaps (auricles)
6. nervous sys are more complex ganglions
7. asexual regeneration or sexual hermaphrodite
II. Eumetazoa
B. Bilateria
a. phylum platyhelminthes
1. class trematoda
flukes often in bile ducts and bloodstreams
1. parasites
2. suckers to hold onto host. tough tegument (outer skin) to resist immune sys
3. inside mostly reproductive organs
4. alternate sexual and asexual throughout life cycles
5. complex life cycles - more than 1 host; essentially internal
6. often need an intermediate
II. Eumetazoa
B. Bilateria
a. phylum platyhelminthes
1. class Cestoda
1. intestinal parasites
2. head = scolex = hooks + suckers
3. inside mostly reprod. organism
4. each proglottid has a complete male/female reprod tract
5. no digest sys - just absorb nutrients you have digested
6. can encyst in muscle
II. Eumetazoa
B. Bilateria
1. have a pseudocoelom
2. body cavity is incompletely lined by mesoderm
3. no muscle around gut
II. Eumetazoa
B. Bilateria
1.phylum rotifera
phylum Rotifera "wheel bearer"
rotifers are Lophotrochozoans

1. mostly aquatic
2. use body cavity as skeleton
3. often parthenogenic
II. Eumetazoa
B. Bilateria
1.phylum nematoda
roundworms (Ecdysozoans)
1. found everywhere; free-living & parasitic
2. have cuticle to protect from host immune sys or gut enzymes
3. only longitudinal muscles
4. sexual, females larger, internal fertilization

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