Bio Unit 2 Cell Structure and Functions

Ch 4 & 5

Lysosome

contains hydrolytic enzymes

digests food

acidic (ph is 5)

phagocytosis

golgi apparatus

sort proteins that were made in ER

packages vesicles and ships them to target site

modifies proteins

myristylation

adds lipids 

glycosylation

adds oligiosaccharides (sugar)

Microbodies 

found in plants and animals 

peroxisomes

lipid degradtion, detoxifies

glyoxysomes

breakdown lipids and converts them to carbohydrates

vacoules

stores organic and inorganic compunds

stores water

three types: food, central vacuole, and contractile

Central Vacuole

only in plants

very useful in storing mass quantity of compounds

Food vacuole

only in animals

performs endocytosis

Contractile vacuole 

only in freshwater protists

removes excess water to stop it from exploding 

Ribosomes:

made up of RNA and proteins
synthesize proteins with their catalytic ability
cytoplasm useful in translation

Smooth ER

synthesizes lipids
partakes in metabolic pathways
detoxifies
stores calcium
glucose storage and release

Rough ER

protein synthesis:
membrane bound proteins for secretion and modification
secretion and modification

Microtubules

Hollow tubules made of tubulin proteins

largest (25 nm)

a-tubulin and b-tubulin

all eukaryotic cells

motility, cell shape, chromosome rearrangement, tracks for movement

Microfilaments

solids rods of intertwining strands 

smallest (7nm)

g-actin and f-actin 

all eukaryotic cells, myosin in animal cells 

motility, shape and change, muscle contraction, cytoplasmic streaming

intermediate filaments

hollow tubes made up with heterogenous proteins

the intermediate (8-10nm)

keratin proteins 

almost in all eukaryotic cells

structural support

cytoskeleton

made up of proteins and help in cell structure and shape

dynein

slides microtubules past another one; used for cilia/flagella
movement

kinesin

movement on microtubules;
used for carrying cargo

cell walls

made up of cellulose
found in plants, fungi, protists, and some
bacteria

what can cellulose be degraded by?

cellulose can be degraded by cellulase
(found in bacteria)

Inside cell membrane out:

plasma membrane → secondary → primary cell wall → middle lamella

fungal cell Wall:

chitin (NAG)
degraded by chitinase which is created by plants

bacterial cell wall

NAM-NAG (peptidoglycan)
degrade by lysozyme

protist cell walls:

long and short chain of polysaccharides and silica

what are the different types of cell junctions?

Tight

Gap

Desmosomes

tight cell junction

no movement between cells

gap junction

small openings between cells

desmosomes:

two cells are connected by proteins (anchoring
junctions)

what is the endosymbiosis theory?

proposes to explain how eukaryotic cells acquired chloroplasts and mitochondria to have their own DNA, proteins, and replicate themselves

• early eukaryotes engulfed aerobic bacteria to becomes mitochondria and then engulfed photosynthetic bacteria to become chloroplasts

What is the con of endosymbiosis theory?

does not explain other eukaryotic features like nucleus, cell division process, import of cytoplasmic proteins into chloroplasts and mitochondria 

how many theories of life are there?

2- panspermia and abiogenisis

what is panspermia theory

meteorite gave rise to complex

what is abiogenisis theory

spontaneous from simple molecules and early life conditions (high temperatures, limited oxygen, high pressure, water, and lightning)

what is the timeline of life

4.5 bya earth formed

4 bya life started (simple bacteria)

2.5 bya cyanobacteria formed

1.7 bya first eukaryotic cell formed

what is the miller-urey experiment?

replicate early earth’s atmospheric condition with hydrogen, methane, water, ammonia, and electrons for lightning

• able to form simple organic molecules (simple sugars, amino acids)

• simple molecules> monomers> polymers

Which came first DNA or RNA?

RNA because it has catalytic abilities:

• it acts an enzyme in protein synthesis

• ability to self replicate

• probiont structure created by RNA

Eukaryotes structure

DNA within nucleus, membrane bound organelles, larger, linear DN, histones winds up DNA, has a nucleus

prokaryotes structure

no nuclei, no membrane bound organelles, circular DNA, DNA in nucleoid region, no endomembrane, small

nucleolus

creation for rRNA

Nuclear Lamina

a lining inside of the nuclear membrane

nuclear pores

allows solute in and out of nucleus like RNA polymeras, DNA polymeras, and DNA binding proteins

Nucleus

double membrane, stores chromosomes, condensed version of chromatin wrapped around histone, site for DNA replication and transcription

microscopy

magnification: how big

resolution: how clear

Light microscope

1000x

0.2 um resolution

colors: bacteria, yeast, chloroplast, living beings

Transmission electro microscope (TEM):

cross section of cells or cell structure

Scanning electron microscope (SEM):

scanning the exterior/interior of the cell

Cell fractionation:

1. harvest
2. grind
3. homogenize
4. centrifuge: collects liquids at the bottom due centripetal force

Gel Electrophoresis

gel moves from cathode
(-) to anode (+)
DNA’s negativity charged due to phosphate group on the backbone

Proteins use PAGE
RNA, DNA uses agarose

animal cells

centrioles

gap junctions

tight junction

lysozyme

desmosomes

plant cells 

chloroplasts

cell wall

central vacuole

plasmodesmata

other forms of chromatography 

thin layer (TLC)

gas chromatography (GC)

high performance liquid (HPLC)

mass spectroscopy 

Sequencing protein, DNA, RNA

Carbohydrates

polar but not charged

use GC and MS

Lipids

non polar, uncharged

use TLC, HPLC, MS, GC

Proteins

positive (+) or negative (-) charge

add SDS to make them very - charge

polyacrylamide gel electrophoresis (PAGE)

Sequencing

DNA, RNA

very negative (-) charged, agarose gel electrophoresis, sequencing of bases, Reverse Transcription Polymerase Chain Reaction (RT-PCR)

Microarray