Eukaryotic Cells

Question 1

Nucleus

Answer 1

-largest organelle
-light microscope can see
-oval
-surrounded by nucleus envelope (two membranes, pores)
-chromosomes (linear DNA and associated with histones)
-Nucleolus (ribosome synthesis)

Question 2

Mitochondria

Answer 2

• Rod or cylinder shape
• in all cells (more in very metabolically active cells)
• 0.5-1.5 micrometers wide
• 3.0-10.0 micrometers long
• smaller than nucleus
• double bound membrane (OUTER: smooth and continuous. INNER: pulled into folds called cristae)
• Matrix (fluid filled inside)
• Energy sites release aerobic respiration
• Contain plasmid DNA
• 70s ribosomes
  ONLY EUKARYOTIC

Question 3

Ribosomes

Answer 3

• Small
  -dense
• mostly attached to RER surface
• consist of 2 subunits
• proteins used for inside cell made on ribosomes in cytoplasm
• proteins used on the outside of cell are made in RER ribosomes
• 80s ribosomes (greater density)

Question 4

Endoplasmic reticulum (RER)

Answer 4

• folded membranes forming sheets
• tubes of flattened sacs in cytoplasm
• flexible
• mobile
• joins with nucleus membrane
  FUNCTION:
  protein transport and folding

Question 5

Smooth ER

Answer 5

No ribosomes
Site if lipid synthesis
Metabolic reactions occur

Question 6

Rough ER

Answer 6

Ribosomes attached to outer surface

Question 7

Golgi body

Answer 7

Tightly packed group of flattered sacs (pancakes)
In all cells (esp. metabolic active ones)
Proteins made on RER are packages into vesicles by Golgi
FUNCTION:
adds carbs to proteins
Produces secretory enzymes
Transports and modifies lipids
Forms lysosomes

Question 8

Lysosomes

Answer 8

Formed from vesicles pinches off from Golgi body
Has digestive molecules
FUNCTION:
destroys unwanted materials
- old organelles
- foreign bodies

Question 9

Chloroplasts

Answer 9

Site of photosynthesis
Double membrane
- inner membrane folded into stacks of membranes called GRANA
GRANA: flattered membranes called thylakoids are was GRANA consists of.
STROMA: aqueous liquid in inner membrane

Question 10

Cell membrane

Answer 10

Double membranes (two layers of phospholipid molecules)
BI- LAYER: Membrane arranged with fatty acid chains pointed inwards (hydrophobic tails, hydrophilic heads)
PROTEIN MOLECULES: in and through membrane, stretch through either or both layers of membrane

Question 11

FUNCTION of cell membrane

Answer 11

Holds cell together
Controls what goes in and out
Maintains homeostasis

Question 12

STRUCTURE of cellulose cell wall

Answer 12

The matrix, that has micro fibrils (tough fibres) surrounds plant cell.
Totally permeable
Strong
Rigid

Question 13

Matrix in cellulose cell wall

Answer 13

Complex sugars such as pectin (acts like glue) and hemicellulose
- long cochaired polysaccharides

Question 14

FUNCTION of cellulose cell wall

Answer 14

Supports plant
protects individual cells
- osmosis won’t effect (swell or pop)
Controls growth
- determined by arrangement of micro fibrils
Protects from physical injury

Question 15

Permanent Valcuole

Answer 15

Surrounded by membrane = tonoplast
Full of ‘sap’, water and dissolved molecules (e.g. sucrose)
Acts as a store
Role in support of cell or plant against turgid pressure