Chapter 4- Cells Flashcards
What are 4 basic features of all cells?
- Plasma membrane
- Semifluid substance called cytosol
- DNA molecules called chromosomes (carry genes)
- Ribosomes (make protein)
What are the two types cells?
Prokaryotic
Eukaryotic
Prokaryotic celled organisms exist in what domains??
Domain Bacteria
Domain Archaea
What domains consist of eukaryotic celled organisms?
Protists , Fungi, Animalia, Plantae
What was the first cell type on earth?
Prokaryotes
Prokaryotic cells’ DNA is located where?
The unbound region called the Nucleoid
What don’t prokaryotic cells have?
Membrane bound organelles
In prokaryotes, what is outside the plasma membrane?
A rigid chemically complex cell wall
What does the cellular wall in prokaryotes do?
Protects the cell
Helps maintain its shape
Some prokaryotes have _______.
Surface projections
What is a flagellum, or flagella? What is their function?
Prokaryotic surface projection.
Allows the cell to move.
Some prokaryotic surface projections do what?
Allow prokaryotic cells to join together, or bond to the substrate
Membrane bound organelles exist in what type of cells?
Eukaryotic
Which is larger? Eukaryotes or Prokaryote?
Eukaryote
What are the 3 components of cell theory?
- All living things are composed of one or more cells
- Cells are the basic units of structure and function in an organism
- Cells come only from existing cells
All living things are composed of _______.
One or more cells
Cells are the basic unit of __________ in an organism.
Structure and function
Cells come only from where?
Existing cells
How big is a human red blood cell?
8 micrometers in diameter
8x(10^-6) meters
What is the smallest cell in the human body?
A sperm cell
Why are cells small?
Because cells are small, they have a higher surface area to volume ratio, allowing for substances to quickly diffuse into and out of a cell
How big is bacteria? Example Eschericia coli (E. coli)
1 X 3 micrometers
What is the formula for surface area?
SA= 6 X (A^2)
SA= 6(sides) X (area of one side squared)
What is the formula for volume?
V= a^3
Volume= length of one side cubed
How high can an electron microscope magnify?
1,000X
Can a compound light microscope see living cells?
Yes
Can an Electron microscope see living cells?
No…it kills the cells being observed
Eukaryotic cells have what type of organelles?
Membrane bound
Eukaryotic cells are ______ than prokaryotic cells.
Larger
When did prokaryotic cells first appear?
3.5 BYA (billion years ago)
When did the first eukaryotic cells appear?
2.0 BYA (billion years ago)
The nucleus is like the _____?
Control center
The cytoskeleton is the ______.
Structure
The Golgi Complex is the ______.
Distribution Center
The lysosomes are like the _____.
Cleaning crew
The endoplasmic reticulum is like the _____.
Assembly Line
The mitochondria are like the _____.
Powerhouses
The ribosomes are like the ______.
Workbenches
The cell membrane is like the _____.
Security gate
The nucleus contains the cell’s _____.
Genetic information
What is the nucleolus?
A prominent structure within the nucleus
The site of ribosomal RNA (rRNA) synthesis
What encloses the nucleus?
The nuclear membrane or nuclear envelope
What does the nuclear envelope consist of?
2 separate phospholipid bilayers with associates proteins
What is the function of the nuclear envelope?
Similar to the plasma membrane, the nuclear envelope regulate passage of material to and from the nucleus.
The nuclear envelope is perforated by what?
Protein lined pores
What do the protein lined pores of the nuclear envelope do?
Regulate entry and exit of large molecules AND
Connect with the cell’s network of membranes called the Endoplasmic reticulum
How is rRNA formed?
Synthesized in the nucleolus according to instructions in the DNA.
How are the subunits of ribosomes formed?
In the nucleolus, proteins are brought in from the cytoplasm and joined with rRNA. They then exit to the cytoplasm the join with other subunits to form function ribosomes
What are the 2 types of RNA?
Ribosomal RNA (rRNA) Messenger RNA (mRNA)
What is mRNA?
What does it do?
Messenger RNA is a transcription of protein synthesizing instructions written in the gene’s DNA.
mRNA moves into the cytoplasm where ribosomes translate it into amino acid sequences of proteins.
What do ribosomes do?
They use the instructions written in the Nucleus by the DNA in the form of mRNA to synthesize amino acid chains to build proteins.
Where can ribosomes be found?
Free ribosomes are suspended in the cytosol
Bound ribosomes are found attached to the outside of the endoplasmic reticulum or the nuclear envelope
What are the two types of ribosomes?
Free ribosomes
Bound ribosomes
How many types of ribosomes are there?
2
What is the purpose of the central vacuole in plant cells?
- Regulates composition of the cytoplasm
- Creates the internal pressure characteristic of plant cells
- Stores various compounds produced by the cell
The endoplasmic reticulum is a _____.
Biosynthetic workshop
How many types of endoplasmic reticulum (ER) are there?
What are they?
- Smooth ER
2. Rough ER
What is characteristic of the Smooth ER?
It lacks attached ribosomes
What is characteristic of Rough ER?
Has bound ribosomes attached to its outer surface of the membrane.
What are the functions of the Rough ER?
Protein synthesis
Protein movement
Protein “proofreading”
Why do we become resistant to drugs and other substances, resulting in increased dosage to get same effects?
As our liver cells are exposed to chemicals, the amount of smooth ER increases as does its detoxifying chemicals. The rate of detoxification increases resulting in increased tolerance to the drug.
The growth of smooth ER in response to one drug can lead to what?
Increase the need for higher doses of other drugs
Barbiturate abuse results in what, relative to other drugs?
Decreased effectiveness of certain antibiotics and other useful drugs
What are the functions of the Smooth ER?
- Synthesis of Lipids: oils, phospholipids, and steroids
- Processing drugs, alcohol l, and other harmful substances
- Storage of Ca ions (calcium ions)
What is a glycoprotein?
Short chains of sugar linked to the polypeptides of proteins during synthesis by the ribosomes
Explain the steps involved with making a protein.
- mRNA, transcribed from DNA in the nucleolus) is read by bound ribosomes of the Rough ER.
- A short sugar chain is often attached to the protein polypeptide, creating a glycoprotein.
After a protein is formed by the ribosomes of Rough ER, what occurs to the protein?
It is then transported to the Golgi Apparatus
What does the Golgi Apparatus do?
Modifies, sorts, and ships cell products
The Golgi Apparatus serves as a _______.
Molecular warehouse and processing station for products manufactured by the ER.
Products travel in transport vesicles from what to what?
ER to Golgi apparatus
One side of the Golgi stack serves as what?
Docking station for transport vesicles from the ER
Unlike the ER, Golgi sacs are ________.
Not connected
What happens when a transport vesicles arrives at the Golgi Apparatus
It fuses with Golgi sac, adding it’s membrane and contents to the receiving side of the Golgi apparatus
As products (proteins) move through the Golgi Apparatus, what occurs?
They are modified
The shipping side of the Golgi apparatus does what?
Dispatches its’ products in vesicles that travel to other sites
What sort of modifications may a protein from the ER undergo in the Golgi apparatus? (2)
- Carbohydrates portions of the glycoproteins are modified, removing some sugars and substituting others
- Phosphate groups may be added to help the Golgi sort molecules into different batches with different destinations
Vesicles from the Golgi go where?
To the plasma membrane for transport outside the cell
What is a second thing that may occur to finished Golgi products?
They may become part of the plasma membrane or other organelle, such as lysosomes