Cells

1. CELL FEATURES
BY ANDREW MAGIGE FRANCIS

2. the main functionality features of cells include
1. cellular structure/organization
2. reproduction
3. metabolism
4. homeostasis
5. heredity
6. response to stimuli
7. growth and development
8. adaptation through evolution

3. structural cellular features
• A cell membrane, cytoplasm and the nucleus are the
three main parts of a cell
• Both plant and animal cells contain the plasma membrane
,cytoplasm, golgi apparatus,endoplasmic reticulum ,
mitochondria,ribosomes , lysosomes,secretory vesicles
• in addition to the above components ,Plant cell have cell
membrane and chloroplast

4. pictorial animal cell

5. pictorial plant cell

6. fungal cell names of the parts of fungal cell
• 1: Hyphal wall 2: Septum 3:
Mitochondrion 4: Vacuole 5:
Ergosterol crystal 6:
• Ribosome 7: Nucleus 8:
Endoplasmic reticulum 9:
Lipid body 10: Plasma
membrane 11:
• Spitzenkörper 12: Golgi
apparatus

7. fungal cells
Similar to animal cells .
in addition they have:
1. cell wall which contains chitin
2. Less definition between cells ,higher fungi hypahe have
septa for passage of substances. primitive fungi have
few or no septa ( coenocytic)
3. Only most primitive fungi have flagela(chytrids)

8. cell structures

9. non -cellular organism (virus)
contains
• lipid envelop
• capsid(protein coat)
• nucleic acid genome

10. reproduction features
• most eukaryotes sexual reproduction could be haploid
(Only a copy of each chromosome )diploid two present
through nuclear fusion (syngamy) and myeiosis
• nuclear division cordinated by cell division ,mitosis,
allowing each daughter nucleus to have one copy of each
chromosome

11. prokaryotic cells
• generally small size 1-10um
• Nucleus absent
• Small or absent ribosomes
• centrioles absent
• mitochondria absent
• found in bacteria,archaea and
blue algae
• unicellular
• telomeres not needed ( circular
DNA)
• present cytoskeleton
eukaryotic cells
• large in size 10-100um
• nucleus present
• Large present ribosomes
• centrioles present
• mitochondria
• found in animals , plants and
protists and fungi
• multicellular
• Telomeres are present (linear
DNA)
• cytoskeleton may be present

12. cell structure and composition
cell is a complex multifunctional unit of an arganism
Plasma membrane
diffusion barrier between cell and its environment (into the cell) and movement in
and out of cell through phospolpidlipidlayer.
 cell wall
Is a rigid external layer designed to provide physical support and rigidity.Is not a
diffusion barrier as seen in the plasma membrane. Cell wall of prokaaryotic cells
contain peptidoglycan substance which is a hy brid between protein and a
polysacharide
 capsule
present in certain procaryotic cells.made of hygroscopic armophours polysacharide
preventing water loss from the cell.

13. Plasmid
much smaller circlar double stranded DNA molecule usually
distinct from the chromosomal DNA.
Mesosome
convoluted membraneous structure formed in prokaryotic
cells by invagination of the cell membrane towards the
interior.
perform aerobic part in aerobic respiration,synthesis of the
cell membrane,replication of DNA and protein synthesis.

14. cont..
 Nucleod
irregular central region part of the cell that carries all or most of genetic
materials.No physical structure enclosing the nucleod.
usualy.Responsible for controlling activity and reproduction of the
prokaryotic cells. The chromosome of a typical prokaryot is circular and
the length is larger than the cell size hence has to be compacted to fit
cytoplasm -gelatinous fluid substance in the interior of cell containing
water,salt ,organic compound .found in both animal and plant cells.
Some intracellular organelles (mitochondrion,nucleus) are enclosed by
membranes that separate them from the cytoplasm

15. Thylakoids
Long strap like structures invaginations of the plasma membrane
found in the photosynthetic prokaryotic cells in
chloroplast.Contains chlorophyl pigment is found that is essential
for absorption light, essdential for photosynthesis.
Endoplasmic reticulum
A system of tubule/membrane enclosed channels within the
cytoplasm of eukaryotic cells except for sperm cell and RBCs.
Rough endoplasmic reticulum-has ribosomes embeded into its
structure hence rough appearance. Role in compartmentalization
of the cell,route for transport of materials within the
cell,synthesize and secretes proteins in the liver , hormones and

16. • Smooth endoplasmic reticulum: has no ribosomes on its
surfaces. Tubular in form.Participates in production of
phospholipids and production of new layers of golgi bodies.
Vacuoles
membrane bound cell organelle in the cytoplasmic part of the
matrix of the cell. It is surrounded by a membrane called
tonoplast. its contents are known as the cell sap. Main
functions include storage for minerals,salts,pigments and
proteins within a cell. Contains water to exerts pressure on the
cell wall, turgor pressure, shaping the cell and protection from
extreme conditions.
Substances taken in (endocytosis) and excreted by exocytosis

17. • Golgi bodies
An organelle that helps package proteins(from the ER) and
lipid molecules into small products called golgi vesicles.
2 types of golgi vessicles
1. Microbodies -fated to remain in the cell. Visble
microscopically.contain materials usually enzyme. examples
are lysosomes
2.Secretory bodies - contains materials secreted (exported0
from the cell eg hormones and pheromones

18. • lysosome
Are membrane bound organelles which carry enzymes
capable of destroying/ breaking down the biological
polymers of the cell and kills the cell.