1.2 Comparing Prokaryotic and eukaryotic cells

Question 1

Common features

Answer 1

• plasma membrane
• Semifluid substance called cytosol
  – Chromosomes (carry genes)
  – Ribosomes (make proteins)

Question 2

Exploring Eukaryotic cells

Answer 2

Animal cells

Fungal cells

Question 3

Cells with chloroplasts

Answer 3

Plant cells

Protistan cells

Question 4

Cell walls of plants

Answer 4

• The cell wall is an extracellular structure that distinguishes plant cells from animal cells
• Prokaryotes, fungi, and some protists also have cell walls
• The cell wall protects the plant cell, maintains its shape, and prevents excessive uptake of water
• Plant cell walls are made of cellulose fibers embedded in other polysaccharides and protei

Question 5

Plant cell walls

Answer 5

• Primary cell wall:
thin and flexible

• Middle lamella:
thin layer between primary walls of adjacent cells

• Secondary cell wall (in some cells):
added between the plasma membrane and the primary cell wall

Question 6

The Nucleus: Information central

Answer 6

• The nucleus contains most of the cell’s genes
• The most conspicuous organelle

• Nuclear envelope encloses the nucleus
– double membrane
– lipid bilayer

Question 7

Ribosomes: Protein factories

Answer 7

• Ribosomes are particles made of ribosomal RNA and protein

• Ribosomes carry out protein synthesis
– In the cytosol
– On the outside of the endoplasmic reticulum or the nuclear envelope

Question 8

The endomembrane system

Answer 8

• Golgi apparatus

* Endosomes, lysosomes, exosomes etc.

Question 9

Vacuoles: Diverse maintenance compartments

Answer 9

Food vacuoles - formed by phagocytes

Contractile vacuoles - found in many freshwater protists, pump excess water out of cells

Central vacuoles - found in many nature plant cells, hold organic compounds and water.

Question 10

Mitochondria and chloroplasts change energy from one form to another

Answer 10

Mitochondria:
are the sites of cellular respiration, a metabolic process that uses oxygen to generate ATP

Chloroplasts:
found in plants and algae, are the sites of photosynthesis

Peroxisomes:
oxidative organelles

Question 11

The evolutionary origins of mitochondria and chloroplasts

Answer 11

have similarities with bacteria

• enveloped by double membrane
• contain free ribosomes + circular DNA molecules
• grow + reproduce somewhat independently in cells

Question 12

The endosymbiont theory

Answer 12

• early ancestor of eukaryotic cells engulfed a nonphotosynthetic prokaryotic
• endosymbiont relationship with host
• merged into single organism, a eukaryotic cell with mitochondrion
• photosynthetic prokaryote was taken up, becoming the ancestor of cells that contain chloroplasts