1.2 Ultrastructure of cells - Eukaryotic cells

Question 1

advantages of eukaryotic compartmentalized cell structure

Answer 1

1- enzymes/substrates much more concentrated since in only one area, not spread out

2- toxins/damaging substances kept in an organelle (limited damage, only to that organelle)

3- conditions like pH maintained at ideal level, which may be diff to levels needed for other processes in cell

4- organelles w/ contents can be moved around within cells

Question 2

10 parts of typical animal cell

Answer 2

• golgi apparatus
• cell membrane
• nucleus
• nucleolus
• mitochondria
• ribosomes
• cytoplasm
• lysome
• smooth ER
• rough ER

Question 3

nucleus

Answer 3

• nuclear membrane = double, has pores
• nucleus contains chromosomes, w/ DNA associated w/ histone proteins
• uncoiled chromosomes spread in nucleus = chromatin (mostly at edge of nucleus)
• where DNA is replicated, transcribed for mRNA, which exported from nucleus pores to cytoplasm

Question 4

rough e.r.

Answer 4

• flattened membrane sacs = CISTERNAE
• attached outside of those are the ribosomes
• synthesise protein for secretion from cell
• it passes into cisternae, carried by vesicles, bud off, moved to golgi apparatus

Question 5

golgi apparatus

Answer 5

• has cisternae
• not as long, they are curved, don’t have attached ribosomes, many nearby vesicles
• processes proteins brought in vesicles from rough e.r.
• most are carried in vesicles to plasma membrane for secretion

Question 6

nucleolus

Answer 6

• inside nucleus

- produces ribosomes

Question 7

smooth e.r.

Answer 7

• synthesizes and transports lipids & steroids

- no ribosomes

Question 8

lysosome

Answer 8

• spherical sacs w/ high concentration of protein
• destroy unwanted structures, entire cells, ingested food in vesicles
• by rupturing of lysosome membrane & release of digestive enzymes

Question 9

mitochondria

Answer 9

• elongated w/ double membrane (inner one is folded to form CRISTAE and increase surface area)
• fluid inside = MATRIX
• produce ATP by aerobic cell respiration - energy source

Question 10

ribosomes

Answer 10

• made of RNA
• synthesize protein
• free ribosomes: release proteins to work in cytoplasm

Question 11

differences b/ween prokaryotic and eukaryotic (9)

Answer 11

1. no nucleus / has nucleus
2. naked dna / dna associated w proteins
3. dna in cytoplasm / dna in enclosed nucleus
4. no mitochondria
5. no ER
6. 70s ribosomes / 80s ribosomes
7. no membrane bound organelles / compartmentalized
8. smaller than 10μm / larger than 10 μm
9. flagella (some, diff structure / flagella and cilia (sometimes)