The cell theory states that all living things are composed of cells; cells are the basic functional unit of life; cells arise only from pre-existing cells; and cells carry their genetic information in the form of DNA.
Name the two distinct groups into which all cells can be categorized.
Prokaryotes and Eukaryotes cells.
What is the key differentiating criterion between prokaryotic and eukaryotic cells?
Eukaryotic cells have membrane-bound organelles; however, prokaryotic cells do not.
(T/F) Bacteria and viruses are examples of prokaryotic cells.
False, bacteria are prokaryotic while viruuses are non-living acellular structures.
Where does respiration occur in the bacterial cell?
The cell membrane is the site of respiration in bacteria.
(T/F) All multicellular organisms are composed of eukaryotic cells.
Which type of eukaryotic cells have a cell wall?
Plant cells and fungal cells have a cell wall.
What is cytosol?
Cytosol is the fluid component of the cytoplasm.
What are the primary components of the cytoskeleton?
The primary components of the cytoskeleton are microtubules, microfilaments, and intermediate fibers.
Define the fluid mosaic model.
The fluid mosaic model states that a cell membrane consists of a phospholipid bilayer with proteins embedded throughout.
Label the parts of the cell membrane:
(a) polar heads
(b) non-polar tails
What is the function of a transport protein?
A transport protein helps move polar molecules and certain ions across the cell membrane.
What is a membrane receptor?
A membrane receptor is a protein (or glycoprotein) that binds to molecules in the extracellular environment.
Can small polar and non-polar molecules easily cross the cell membrane?
Yes, because of their size, small polar and non-polar molecules can easily traverse the cell membrane.
How does a large charged molecule cross the cell membrane?
A large charged particle usually crosses the cell membrane with the help of a carrier protein.
(T/F) The nucleus is surrounded by a single-layered membrane.
False, the nuclear membrane is double-layered.
How is material exchanged between the nucleus and the cytoplasm?
The nuclear membrane contains nuclear pores that selectively allow for the exchange of materials.
What is a histone?
A histone is a structural protein complexed with eukaryotic DNA to form a chromosome.
What is the function of the nucleolus?
The nucleolus synthesizes ribosomal RNA (rRNA).
What is the function of a ribosome?
A ribosome is the site of protein translation (assembly) during protein synthesis.
What is the general function of endoplasmic reticulum?
Endoplasmic reticulum is involved in the transport of materials throughout the cell.
What is the function of the smooth endoplasmic reticulum (smoot ER)?
Smooth ER is the site of lipid synthesis and poison detoxification, and it is involved in protein transport within the cell.
What is the function of the rough endoplasmic reticulum (RER)?
RER serves as an attachment point for ribosomes, which functions in protein synthesis for membrane bound proteins and proteins to be excreted from the cell.
(T/F) Proteins synthesized by RER are secreted directly into the cytoplasm.
False, they are secreted into the cisternae of RER and then sent to smooth ER, where they are secreted into vesicles.
What is the function of the Golgi apparatus?
The Golgi apparatus receives vesicles from the smooth ER, modifies them, and repackages them into vesicles for distribution.
What happens to a secretory vesicle after it is released from the Golgi apparatus?
A secretory vesible from the Golgi fuses with the cell membrane to release its contents via exocytosis.
(T/F) Vesicles and vacuoles are membrane-bound sacs involved in transport and storage of cellular materials.
What is a lysosome?
A lysosome is a membrane-bound vesicle that contains hydrolytic enzymes involved in intracellular digestion.
(T/F) Lysosomes fuse with endocytotic vesicles and help digest their content.
How does the pH in the interior of a lysosome compare with the pH in the rest of the cell?
The interior of a lysosome is acidic and therefore has a lower pH than the rest of the cell.
What would happen if a lysosome released its contents into the cytoplasm?
The hydrolytic enzymes of the lysosome would digest the organelles and kill the cell. This process is known as autolysis.
What is the function of peroxisomes?
Peroxisomes make hydrogen peroxide and digest fats into smaller molecules.
What is the function of mitochondria?
Mitochondria are the sites of aerobic respiration and supply most of the cells energy.
(T/F) Mitochondria have their own circular DNA.
Do mitochondria replicate in a manner similar to a cell's other organelles?
No, they replicate via binary fission.
(T/F) Mitochondria and chloroplasts are similar structures and both are considered to be semi-autonomous.
What is the function of a cell wall?
A cell wall protects the cell from external stimuli and desiccation.
What is the function of centrioles?
Centrioles are involved in spindle formation during cell replication. They are found only in animal cells.
What is a centrosome?
The centrosome is the region of a cell that contains the centrioles.
What is the function of the cytoskeleton?
The cytoskeleton gives mechanical support, maintains the cell's shape and functions in motility.
What is the function of microtubules?
Microtubules maintain the cell shape, form the spindle apparatus and provide tracks along which organelles can move.
(T/F) Cilia and flagella are specialized arrangements of microfilaments and function in cell motility.
False, while ciliar and flagella do function in cell motility, they are composed of microtubules.
(T/F) Microfilaments are solid rods of actin and are involved in cell movement and cell wall support.
Name the following cellular structures:
1. Cell membrane
2. Pinocytic Vesicle
7. Endoplasmic Reticulum
10. Nuclear Membrane
11. Golgi Apparatus
(T/F) Simple diffusion is a passive process that requires energy.
False, simple diffusion is a passive process and therefore DOES NOT require energy.
Osmosis is the simple diffusion of water from a region of lower solute concentration to a region of higher solute concentration.
What would happen to a cell is it were put in a hypertonic solution?
A hypertonic solution would cause water to flow out of a cell and cause the cell to shrink.
(T/F) A hypotonic solution will cause water to flow into a cell causing it to swell.
A medium and a cell are said to be isotonic when the solute concentrations of the medium and the cell are equal.
Define facilitated diffusion.
Facilitated diffusion is the net movement of dissolved particles down their concentration gradient with the help of carrier molecules.
(T/F) Facilitated diffusion requires energy.
False, all forms of diffusion, including facilitated diffusion, are passive processes.
Define active transport.
Active transport is the net movement of dissolved particles against their concentration gradient with the help of carrier molecules. This process requires ATP.
(T/F) Active transport requires energy.
What is endocytosis?
Endocytosis is a process in which the cell membrane invaginates , forming an intracellular vesicle containing extracellular medium.
What is exocytosis?
Exocytosis is a process in which a vesicle within the cell fuses with the cell membrane and releases its contents to the extracellular medium.
What is the difference between pinocytosis and phagocytosis?
Pinocytosis is the endocytosis of liquids and small particles, whereas phagocytosis is the endocytosis of large particles.
What are the four basic types of tissue found in the body?
The four basic types of tissue found in the body are:
What are the components of a virus?
A protein coat and nucleic acid.
What kinds of nucleic acid are found in viruses?
Single- or double- stranded DNA or RNA.
(T/F) Viruses are obligate intracellular parasites.
What is a bacteriophage?
A bacteriophage is a virus that infects bacteria only.
What is the genertic material of a virus?
The genetic material of a virus can be DNA or RNA.