microscopes and cell composition

Question 1

light microscope

Answer 1

visible light is passed through a specimen and then through glass lenses - lense bends light so image is magnified
- sees bigger things
- larger EM waves
- living cells
- cane stiane for flagged

Question 2

parameters of microscopy

Answer 2

magnification, resolution, and contrast

Question 3

organelles

Answer 3

membrane-enclosed compartments

Question 4

scanning electron microscopes (SEMs)

Answer 4

focus a beam of electrons onto the surface of a specimen, image that looks 3-D
- looks at surface
- dead cells

Question 5

transmission electron microscopes (TEMs)

Answer 5

focus a beam of electrons through a specimen
- internal structure
- dead cells

Question 6

cell fractionation

Answer 6

breaks up cells and separates the components, using centrifuge
- largest parts pellet first

Question 7

prokaryotic cells

Answer 7

bacteria and archea
- no nucleus
- DNA in unbound region called nucleic (small circular duplex)
- no-membrane bound organelles
- unicellular, small
- rigid cell wall
- small internal organization, little compartmentalization
- divide by fission

Question 8

eukaryotic cells

Answer 8

protists, fungi, animals, plants
- DNA in nucleus bound by double membrane
- internal membranes that divide cell into organelles
- nucleus

Question 9

nucleus

Answer 9

contains most of cell’s genes and most obvious organelle
- nucleus envelope
- double membrane (lipid bilayer)
- nucleus pores

Question 10

difference in plant and animal cells

Answer 10

animal: centrosome
plant: central vacuole, chloroplasts, cell wall

Question 11

the endomembrane system

Answer 11

regulates protein traffic an performs metabolic functions in the cell
- nucleus envelope
- ER
- Golgi apparatus
- lysosomes
- vacuoles
- plasma membrane
these are either continuous or connected through transfer of vesciles

Question 12

all cells

Answer 12

• plasma membrane
• cytosol
• chromosomes
• ribosomes

Question 13

ratio of SA(n2) to V(n3) is critical

Answer 13

small cells have greater SA to V ratio (SA increases while V remains constant)

Question 13

Ribosomes

Answer 13

complexes of ribosomal RNA and protein
- carry out protein synthesis
- free (cytosol) and bound (ER or nucleus envelope)

Question 14

The endoplasmic reticulum

Answer 14

accounts for more than half go the total membrane - continuous with nucleur envelope
- Smooth ER (no ribosomes)
- Rough ER (ribosomes)

Question 15

smooth ER function

Answer 15

• synthesizes lipids
• detoxifies drugs and poisons
• stores calcium ions

Question 16

rough ER function

Answer 16

• secrete glycoproteins (covalently to bonded proteins and carbs)
• distributes transport vesicles
• is a membrane factory

Question 17

The Golgi Apparatus

Answer 17

flattened membranous sacs called cisternae
- modifies products of ER
- makes macromolecules
-sorts and packages materials into transport vesicles
-cis face (received) and trans face (ships)

Question 18

Lysosome

Answer 18

a membranous sac of hydrolytic enzymes that can digest macromolecules
- work best in acidic environment and 3-D shape protects them
- Tay-Sachs disease: lysosomes can’t degrade certain glycolipids due to defect in enzyme

Question 19

Vacuoles

Answer 19

large vesicles derived from the ER and Golgi
- solution inside differs from cytosol
- Food Vacuoles: formed by phagocytosis
- Contractile Vacuoles: fresh aware protists, pumps out excess water
- Centra Vacuoles: plant cells, holds organic compounds + water
- enzymatic hydrolysis

Question 20

Mitochondria

Answer 20

the sites of cellular respiration
- smooth outer membrane, folder inner membrane called cristae
-cristae divided into inter membrane space and mitochondrial matrix

Question 21

cellular respiration

Answer 21

a metabolic price that uses oxygen to generate ATP

Question 22

Chloroplasts

Answer 22

green pigment chlorophyll and enzymes and other molecules that function in photosynthesis

Question 23

Peroxisomes

Answer 23

specialized metabolic compartments bounded by a single membrane
- produce hydrogen peroxide and converts to water

Question 24

The endosymbiont theory

Answer 24

1. eukaryotic cell engulfs non-photosynthetic prokaryotic cell
2. makes eukaryotic cell with mitochondria
3. this takes a photosynthetic prokaryote
4. forms eukaryotic cell with chloroplasts and mitochondria
   - both mitochondria and chloroplasts are enveloped by a double membrane, contain ribosomes, multiple circular DNA molecules and grow/reproduce

Question 25

cytoskeleton

Answer 25

network of fibers through cytoplasm that organizes cell’s structures and activities

Question 26

cytoskeleton functions

Answer 26

• support cell and maintain shape
• provides anchorage
• interacts with motor proteins to produce motility
• things “walk” along tracks