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Human cell-structural anatomy ppt
1. The human cell 4/10/21
Objectives
By the end of this session, the learner should
be able to:
Define the human cell
Identify the structure of the cell
Enumerate the organelles of the cell
Discuss the functions of the organelles of
the cell
Assignment: draw and label the structures
of the human cell
1
2. Introduction to Human Cells
The human cell is the basic functional
and structural unit of all life
All living things are composed of cells,
cell parts, or cell products.
Cells can only be observed under
microscope
All cells get food, remove waste and
reproduce
2
8. Two types of cells are determined by the
number of Cells
Organisms may be:
• Unicellular –
composed of one cell
• Multicellular-
composed of many
cells that may
organize
9. Cells May be Prokaryotic or
Eukaryotic
Prokaryotes include bacteria &
lack a nucleus or membrane-bound
structures called organelles
Eukaryotes include most other
cells & have a nucleus and
membrane-bound organelles (plants,
fungi, & animals)
14. Structurally, the cell has three key
sections
Plasma membrane
Nucleus
Cytoplasm
The plasma membrane AKA Cell
membrane is a bilayer of lipids and
proteins
This layer allows only specific materials
to enter and exit the cell through the
pores
14
15. Surrounding the Cell
– Lies immediately
against the cell wall
– Made of protein and
phospholipids
– Selectively
permeable
Cell membrane
17. This phospholipid bi-layer membrane acts as
a selectively permeable gateway for the
passage of substances into and out of the
cell!
Boundary between cell and environment.
Controls materials that enter and exit the
cell.
Example: oxygen & nutrients IN -wastes
OUT
The membrane also contains proteins
embedded within its phospholipid layers
that act to encourage molecular movement,
or as recognition molecules.
17
18. Organelles
Cell organelle is a specialized
entity present inside a particular
type of cell that performs a
specific function
Found throughout cytoplasm
18
19. The following are some Cell Organelles
Nucleus
Ribosomes
Endoplasmic reticulum
Golgi apparatus
Mitochondria
Vesicles
Vacuoles
19
20. Organelles Found in Cells
Examples of Organelles include:
• Endoplasmic reticulum (rough & smooth)
– canals for movement
• Golgi Bodies – wrap & export proteins
• Ribosomes – makes proteins
• Nucleolus – makes ribosomes
• Lysosomes – digests & gets rid of
wastes
21. 21
THE NUCLEUS
The nucleus is the of command center of the
cell.
Surrounded by a nuclear envelope - double
membraned, 4 layers thick.
Pores in the nuclear envelope allow chemical
messages to move in and out of the nucleus.
Contains DNA - made up of long strands called
chromatin threads.
The nucleolus (inside the nucleus) produces
ribosomes.
22. More on the Nucleus
22
– Each cell has fixed
number of
chromosomes that
carry genes
– Genes control cell
characteristics
Nucleus
23. Control Organelle
23
– Controls the normal
activities of the cell
– Contain the DNA
– Bounded by a
nuclear membrane
– Contains chromosomes
Nucleus
24. Nucleolus
Cell may have 1 to 3
nucleoli
Inside nucleus
Disappears when cell
divides
Makes ribosomes that
make proteins
26. ENDOPLASMIC RETICULUM (ER)
Bilayer of lipids used for transport
within the cell.
2 TYPES:
Smooth E.R. does not have ribosomes
attached and are known to produce
lipids.
Rough E.R. have ribosomes attached
and are known for both protein
synthesis and lipid synthesis and
transport.
27. Golgi Bodies-“Packaging Factory”
Stacks of flattened
sacs
Have a shipping side & a
receiving side
Receives, sorts &
modifies proteins made
by ER
Transport proteins
inside protective called
vesicles
Transport
vesicle
28. Lysosome-(“stomachs” of the cell or “suicide sacs”
Contain digestive
enzymes
Break down food and
worn out cell parts for
cells and viruses or
bacteria.
Programmed for cell
death (lyse & release
enzymes to break down &
recycle cell parts)
29. Centrioles
Centrioles are only found in animal cells.
These are two small bundles of
cytoskeleton arranged at right angles to
one another & surrounded by dense
cytoplasm.
Centrioles aid in cell division in animal
cells.
31. Vacuoles
Vacuoles are storage vessels found within
the cell.
Plant cells usually have large vacuoles while
animals have vacuoles that are small or even
absent.
Vacuoles can store food, water, or waste
products.
A contractile vacuole is a specialized vacuole
to remove excess water from unicellular
aquatic organisms.
