Cells and organelles

1. Cells and organelles
Lecture 2
Chapter 4
24/10/2021
Lecture2, cells and organelles

2. Learning Outcomes
By the end of this lecture, student would be
able to understand
Structure and function of nucleus,
mitochondria and plastids.
The endosymbiont theory

3. Domains of life
Lecture2, cells and organelles
 Prokarya
 Eukarya
Bacteria
Archaea
Ancestral cell
Bacteria
Eukarya
Archaea

4. 4.3 The Eukaryotic Cell in
Overview: Structure and
Function
◦ The structural complexity of eukaryotic cells is
illustrated by the typical animal and plant cells.
◦ A typical eukaryotic cell has a plasma
membrane, a nucleus, membrane-bounded
organelles, and the cytosol interlaced by a
cytoskeleton.
◦ In addition, plant and fungal cells have a rigid
cell wall surrounded by an extracellular matrix
© 2017 Pearson Education, Ltd.

5. © 2017 Pearson Education, Ltd.

6. © 2017 Pearson Education, Ltd.

7. The nucleus and the nuclear envelope
Lecture2, cells and organelles

8. Presence of a Membrane-
Bounded Nucleus
 A eukaryotic cell has a true, membrane-
bounded nucleus.
 The genetic information of a bacterial or
archaeal cell is folded into a compact
structure called the nucleoid and is
attached to the cell membrane.
© 2017 Pearson Education, Ltd.

9. © 2017 Pearson Education, Ltd.

10. Lecture2, cells and
organelles
Nucleu
s
Nucleus
Nucleolu
s Chromatin
Nuclear
envelope: Inner
membrane
Outer membrane
Nuclear pore
Pore
comple
x
Pore complexes (TEM). Nuclear lamina (TEM).
Close-up
of nuclear
envelope
Ribosom
e
1 µm
Rough
ER 1
µm
Surface of
nuclear
envelope.
0.25µm
Outer & inner membranes= nuclear
envelope
Pores; hydrophilic
water soluble
molecules
✓Ribosomal subunits
✓mRNA
✓Chromosomal
proteins
✓Enzymes
Nucleolu
s

11. Energy-Related Organelles
The two energy-related organelles of
eukaryotes are chloroplasts and
mitochondria.
Both organelles house energy in the form of
ATP.
Lecture2, cells and organelles

12. Mitochondria
Lecture2, cells and
organelles
➢The number and location of
mitochondria within a cell is directly related to
the role of cells (Muscle, sperm cells).
➢Round or oval in shape.
➢Produce energy for the cell’s activities
➢Oxidation of sugars and production of
cellular fuel.
➢POWERHOUSE of the cell

13. Mitochondria are enclosed by two membranes
• A smooth outer membrane
• An inner membrane folded into crista
The matrix contains DNA, proteins, RNA and ribosomes

14. Lecture2, cells and organelles
The number and location of mitochondria within a cell can often be related
directly to their role in that cell.
Localization of the Mitochondrion Within a Sperm Cell. The mitochondria present
in a sperm cell are coiled tightly around the axoneme of the tail.
(a) A schematic drawing of a sperm.
(b) An electron micrograph of the head and the midpiece of a sperm cell from a
marmoset monkey (TEM).