22 terms

MCAT Biology - The cell

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