Module 5.3 Cell Organelles Flashcards
What is the first principle of Cell Theory?
All living organisms are made of 1 or more cells
What is the smallest unit of life according to Cell Theory?
The cell
Cells come from _______.
pre-existing cells
All cells have
- Plasma membrane
- DNA
- Ribosomes
- Cytosol/cytoplasm
Plasma membranes are
strong, flexible and semi-permeable
DNA is a coded
“instruction book” for the cell
Ribosomes are
small structures used by the cell for making proteins
Cytosol/cytoplasm is the
fluid inside the cell
All life can be divided into 2 main categories
*Prokaryotes
*Eukaryotes
Prokaryotes have no
nucleus
What are Prokaryotes?
Single-celled bacteria without membrane-bound organelles
Prokaryotes have
Plasma membrane, cell wall, some have capsule, ribosomes, cytoplasm, and dna
Many Prokaryotes also have
pili (hairs on the surface)
Ribosomes are the site of
protein synthesis. Where protein is made
Cytosol or cytoplasm contains
water, biomolecules, ions, and other substances
What is the shape of Prokaryotic DNA?
Usually circular, called loop of DNA
Prokaryotes DNA is located in the
center of the cell in the nucleoid area
Prokaryotes DNA is usually
smaller than eukaryotes
Eukaryotes have _______.
membrane-bound organelles
Eukaryotes have the following characteristics like all cells
- plasma membrane
- cell wall (for plants and fungi)
- ribosomes
- site of protein synthesis
- cytosol or cytoplasm
- DNA
How is Eukaryotes DNA arranged
Linear arranged in chromosomes in the nucleus of the cell
What is the main difference between Prokaryotic and Eukaryotic cells in terms of size?
Prokaryotes are usually smaller than Eukaryotes
List the four kingdoms of Eukaryotes.
- Protists
- Fungi
- Plants
- Animals
Protists are
single-celled, water-dwelling
What do plant cells have that animal cells do not?
Cell walls, chloroplasts, and one large central vacuole
Cell walls are made of
polysaccharide cellulose
Plant cell walls make plant cells
rigid
Chloroplasts are
green organelles for photosynthesis (energy)
What is the function of chloroplasts?
Photosynthesis
Plant central vacuole is a
water-filled sac inside the cell
What is the central vacuole’s role in plant cells?
Often stores nutrients and waste
Usually the largest organelle in the eukaryotic cell
nucleus
The nucleus organelle contains the
DNA necessary for the cell to be alive, RNA, and proteins
The nuclear envelope protects the
DNA from DNAse enzymes in the cytosol that destroy DNA
What protects the DNA in the nucleus?
Nuclear envelope
How thick is the nuclear envelope?
It’s 2 phospholipid bilayers thick
Why is the nuclear envelope so thick?
Double the membrane for extra protection
What are pores in the nuclear envelope used for?
Allow molecules to enter and leave the nucleus
What controls what enters and leaves the nucleus?
256 polypeptides
The nucleolus is 1 or more
region in the nucleus that is usually stained darker than the rest
What is the role of the nucleolus?
Involved in processing RNA and making ribosomes
The nucleolus does not have a
membrane
What are all part of the endomembrane system?
- Smooth Endoplasmic reticulum (SER)
- Rough endoplasmic reticulum (RER)
- Golgi apparatus/Golgi body
- Transport vesicles
Smooth Endoplasmic reticulum (SER) contains
enzymes of many metabolic processes.
Smooth Endoplasmic Reticulum (SER) synthesizes
Lipids such as phospholipids
In ovaries and testes, Smooth ER
makes sex hormones
In liver, Smooth ER
detoxifying enzymes to remove alcohol, etc, from the body
In muscle cells, Smooth ER
stores calcium ions
Rough ER contains
ribosomes
What is the function of the Rough Endoplasmic Reticulum (RER)?
Site of protein synthesis
Rough ER is contiguous/wrapped around the
nuclear envelope
Golgi Apparatus/Golgi Body is a
series of flattened membranes looking a little like a cut onion
The Golgi apparatus acts as
“receiving and shipping department” for the cell
The Golgi apparatus receives, process and adds what?
receives newly made proteins, processes new proteins, & adds “zip codes” to direct proteins to correct organelle
What is the function of transport vesicles?
Carry proteins and other substances to and from the Golgi
Step 1 of the Protein Processing Pathway involves proteins being made on _______.
ribosomes attached to the nuclear envelope and rough ER
Step 2 of the Protein Processing Pathway involves new proteins passing
into the middle of the rough ER and pinched off in vesicles
Step 3 of the Protein Processing Pathway involves
Vesicles with their cargo of proteins travel to the Golgi, where the proteins are processed
Mature proteins are pinched off into new vesicles
Step 4 of the Protein Processing Pathway involves
these vesicles either fuse with the plasma membrane to deliver the proteins to the rest of the body or get shipped to other organelles
Lysomes is a
vesicle, filled with digestive enzymes
Different lysosomes have different functions like
Protists engulf food in vacuole.
White blood cells engulf invading bacteria
It’s always about breaking down
What do lysosomes contain?
Digestive enzymes
Lysosomes recycle
worn out organelles, releasing nutrients into cell
What disease is associated with not having enough lysosomes or them not working properly?
Tay-Sachs disease. The lysosomes don’t break down a brain lipid so brain cells accumulate this lipid and don’t function well
What is the powerhouse of the cell and what does it produce?
mitochondria, it produces most of the cell’s energy as ATP
What is the main function of mitochondria?
Produce most of the cell’s energy as ATP
Mitochondria structural features
- Outer membrane
- Inner membrane
- Matrix
The Mitochondria outer membrane is
relatively smooth and surrounds the mitochondria
The Mitochondria inner membrane is
Very convoluted, with folds called cristae
The Mitochondria matrix is
Fluid-filled center, like “cytosol” of the mitochondria
The Mitochondria matrix contains
circular DNA (its own DNA) and ribosomes
What is unique about mitochondrial DNA?
Inherited only from the mother
Mitochondrial DNA is often used in
DNA fingerprinting and determining haplotypes—our ancestors
Ribosomes are the cell’s
protein factories
What are ribosomes made of?
Large and small subunits of protein and rRNA
Ribosomes are found on
- Rough ER
- Free in the cytoplasm
Cytoskeleton is another organelle that is the
“skeleton of the cell”
Cytoskeleton is a network of
protein fibers (Microtubules , Microfilaments, and Intermediate filaments)
What is the cytoskeleton’s function?
- Maintain shape of the cell
- Allow movement of the cell
- “Roadways” to transport vesicles and organelles around the cell.
- Anchor and stabilize organelles so nucleus remains in middle of the cell usually
Cilia and Flagella are
extensions of the plasma membrane made of microtubules in a circle
What are cilia?
Hair-like projections that bend in unison
Specialized tissues in many multi-celled animals stay stationary and use cilia to
beat to move liquids
Flagella are
long whip-like projections from cells usually used for movement
Flagella are used primarily for _______.
movement
Microvilli are
Small projections from surface of some cells made by infolding of plasma membrane
What are microvilli used for?
Increase surface area of the cell for absorption of water and nutrients
Microvilli are found in
kidney and cells of digestive tract
What are centrosomes made of?
Two centrioles made of microtubules
Centrosomes are found in
animal cells only
Centrosomes are used to _______.
separate chromosomes during mitosis
