Download Cell Organelles

Cell Organelles
Section 3.2, Part 3
1
Objectives
• SWBAT describe the internal structure of
eukaryotic cells.
• SWBAT visualize the structures and functions
of organelles in plant and animal cells.
2
Vocabulary
•
•
•
•
•
•
•
•
•
•
•
•
•
Cytoskeleton (microtubules, intermediate filaments, microfilaments)
Nucleus
Rough endoplasmic reticulum (rough ER)
Smooth endoplasmic reticulum (smooth ER)
Ribosome
Golgi apparatus
Vesicle
Mitochondrion (mitochondria is plural)
Vacuole
Lysosome
Centriole
Cell wall
Chloroplast
3
Mitochondria (Mitochondrion)
• Mitochondria supply energy to the cell.
• They are bean shaped and have two
membranes.
– The inner membrane has many folds, which
greatly increases surface are.
– The inner folds are where, through a series of
chemical reactions, the food you eat is
transformed into useable energy.
4
Mitochondria
• Mitochondria have their own DNA (in a ring
like bacterial DNA) and their own ribosomes.
This suggests that
mitochondria were originally
free-living prokaryotes that
were taken in by larger cells –
creating a symbiotic
relationship.
5
Vacuole
• Fluid-filled sacs used for the storage of materials
used by cells.
– This may include water, food molecules, inorganic ions (not
carbon), and enzymes.
– Animal cells contain small vacuoles while plants have large
central vacuoles.
6
Lysosomes
• They contain enzymes, with which they break
down damaged or worn-out cell parts.
– They also defend a cell from invading bacteria and
viruses.
– They engulf and digest targeted molecules. The
broken down molecule is then moved to the
cytoplasm where its parts are used again by the cell.
– They are numerous in animal cells but rare in plant
cells.
– Lysosomes are made by the Golgi apparatus.
7
Lysosomes
The lysosomal enzymes are
made in the rough ER in an
inactive form. Vesicles
pinch off from the rough ER
and carry the enzymes to
the Golgi apparatus. There,
the enzymes are packaged,
activated and pinched off
from the Golgi membrane
as formed lysosomes.
8
Cell Walls
• Surrounds the cell membrane in plants.
• Cell walls are rigid and give protection,
support and shape to plant cells.
• Cell walls can adhere to each other to help to
support an entire organism.
– Example: wood in a tree trunk consists of dead
cells whose cell walls continue to support the
entire tree.
9
Chloroplasts
• They carry out photosynthesis!
– They convert solar energy into energy-rich
molecules (i.e. glucose) the cell can use.
– They contain chlorophyll
• They are similar to mitochondria in that they
have a highly-folded inner membrane.
• They have their own bacteria-like DNA and
ribosomes like mitochondria.
10
Choloroplast
11
Centrosome and Centrioles
• The centrosome is a small region of the
cytoplasm that produces microtubles.
– In animal cells it contains 2 small structures called
centrioles.
• Centrioles are cylinder-shaped organelles made
of short microtubles arranged in a circle.
• When the cell is ready to divide, the centrosome
and centrioles double and the 2 new
centrosomes move to opposite ends of the cell.
12
Centrosomes and Centrioles
• They form spindle fibers which attach to DNA and
pull the chromosomes apart during cell division
(mitosis and meiosis).
13