Chapter 3 - Cellular level (Pt2) Flashcards
Discuss the components of the cytoplasm Compare and contrast mitosis and meiosis Understand the effects aging has on the cell
Q: What are the two components of the cytoplasm?
A: The cytoplasm consists of the cytosol and organelles.
Q: What is the cytosol?
A: The cytosol, or intracellular fluid, makes up about 55% of the cell’s volume and is primarily composed of water, ions, nutrients, proteins, lipids, ATP, and waste products.
Q: What percentage of the cytosol is water?
A: The cytosol is 75-90% water.
Q: What key process occurs in the cytosol?
A: Glycolysis, the breakdown of glucose to produce ATP, occurs in the cytosol.
Q: What is the cytoskeleton?
A: The cytoskeleton is a network of protein filaments in the cytosol that maintains cell shape and supports organelles.
Q: What are the components of the cytoskeleton?
A: The cytoskeleton is composed of microfilaments, intermediate filaments, and microtubules.
Q: What are microfilaments, and what do they do?
A: Microfilaments are the thinnest components, made of actin and myosin, providing mechanical support and enabling movement like muscle contraction and cell division.
Q: What roles do intermediate filaments play in the cell?
A: Intermediate filaments provide structural reinforcement, hold organelles in place, and help shape the cell.
Q: What are microtubules, and what are their primary functions?
A: Microtubules are cylindrical filaments made of tubulin, providing support, structure, and enabling transportation within the cell.
Q: What are organelles?
A: Organelles are specialized structures within cells that have unique shapes and functions to support growth, maintenance, and reproduction.
Q: Why do different cellular reactions occur in separate organelles?
A: To prevent interference between reactions and to compartmentalize processes, allowing for specific conditions and enzymes to be maintained.
Q: What determines the type and number of organelles in a cell?
A: The cell’s specific role or function determines the type and number of organelles it contains.
Q: How do organelles contribute to homeostasis within a cell?
A: While they have distinct functions, organelles work together to maintain balance and proper functioning within the cell.
Q: Why is the nucleus often discussed separately from other organelles?
A: Because the nucleus controls the cell’s activities and contains the genetic material.
Q: What is a key feature of organelles in terms of cell processes?
A: Each organelle contains specific enzymes for their tasks, acting as compartments for certain processes.
Q: How do organelles contribute to cellular efficiency?
A: By compartmentalizing processes, organelles allow for specialized environments and efficient reaction conditions tailored to specific tasks.
Q: What is the primary function of the cytoskeleton?
A: The cytoskeleton helps determine cell shape and organizes organelles, aiding in movement, absorption, and support.
Q: What are the three types of filaments in the cytoskeleton?
A: Microfilaments, intermediate filaments, and microtubules.
Q: What are microfilaments made of, and what is their function?
A: Microfilaments are made of actin and myosin; they aid in movement such as muscle contraction and cell division and provide support.
Q: Where are microfilaments primarily located, and what do they support?
A: They are found at the cell’s edge and support cell extensions like microvilli for absorption.
Q: What is the role of intermediate filaments in the cell?
A: Intermediate filaments provide strength, hold organelles like the nucleus in place, and help cells attach to each other.
Q: How are microtubules formed, and what are their functions?
A: Microtubules are formed from tubulin at the centrosome; they determine cell shape and assist in moving organelles, chromosomes, and structures like cilia and flagella.
Q: What role do microtubules play in cellular movement?
A: They assist in the movement of organelles, chromosomes during cell division, and structures like cilia and flagella to facilitate locomotion.
Q: What are cilia?
A: Cilia are hairlike projections that extend from the cell surface, helping move fluids along the cell surface.
Q: How do cilia contribute to cell function in the respiratory tract?
A: They move mucus and trapped particles away from the lungs to prevent interference with proper cell function.
Q: Describe the movement of cilia.
A: Cilia move with a power and recovery stroke, similar to an oar moving through water, which enables them to move fluids over the cell’s surface.
Q: What role do microtubules play in cilia?
A: Microtubules are structural components of cilia,.
Q: How are cilia anchored to the cell?
A: Cilia are anchored to the cell by basal bodies, which also assist in the assembly of cilia and flagella.
Q: What can impede ciliary action and affect lung function?
A: Conditions like cystic fibrosis can cause thick mucus, which hinders ciliary action and affects lung function.
Q: What is the purpose of cilia’s coordinated beating?
A: The coordinated beating moves fluids, such as mucus, efficiently across the cell’s surface to clear debris and foreign particles.
Q: What are flagella?
A: Flagella are long, whip-like structures similar to cilia but much longer, used to move entire cells.
Q: How do flagella differ from cilia in structure and function?
A: Flagella are longer than cilia and primarily function to move entire cells, whereas cilia often move fluids over the cell’s surface.
Q: How does a flagellum move the cell?
A: A flagellum moves in a wave-like pattern to propel the cell forward.
Q: What is the only example of a flagellum in human cells?
A: The sperm’s tail, which helps it swim toward the egg in the uterine tube.
Q: Describe the motion of a flagellum.
A: The flagellum moves by wiggling in a wave-like pattern to push the cell forward.
Q: What is the nucleus, and why is it prominent in the cell?
A: The nucleus is a round or oval structure that is usually the most noticeable part of a cell, housing DNA and controlling cell activities.
Q: How do the number of nuclei vary in different cells?
A: Most cells have one nucleus, but some, like red blood cells, have none, while others, like muscle cells, have several.
Q: What is the nuclear envelope?
A: The nuclear envelope is a double-layered membrane surrounding the nucleus, made of lipid bilayers, with the outer layer connected to the rough ER.
Q: What are nuclear pores, and what is their function?
A: Nuclear pores are large openings in the nuclear envelope that control the movement of substances between the nucleus and the cytoplasm.
note: The nuclear envelope is a double-layered membrane surrounding the nucleus, made of lipid bilayers, with the outer layer connected to the rough ER.
Q: How do large molecules like RNA and proteins move through the nuclear pores?
A: Large molecules require active transport, moving selectively through nuclear pores with energy input.
Q: What is the nucleolus?
A: The nucleolus is a cluster of DNA, RNA, and proteins within the nucleus that produces ribosomes and is prominent in cells synthesizing large amounts of protein, such as skeletal muscle cells.
Q: Why is the nucleolus prominent in certain cells like skeletal muscle cells?
A: Because it produces ribosomes, which are crucial for protein synthesis, and these cells have high protein synthesis demands.
Q: What are the hereditary units within the nucleus called?
A: The hereditary units are called genes.
Q: How are genes organized in the nucleus?
A: Genes are arranged along chromosomes.
Q: What are chromosomes composed of?
A: Chromosomes are made up of DNA and a histone protein complex.
Q: What is the role of histone proteins?
A: Histone proteins provide structural support for DNA, helping to organize it into chromatin.
Q: What are nucleoli, and what is their function?
A: Nucleoli are clusters of proteins, DNA, and RNA in the nucleus that make ribosomal RNA (rRNA) and assemble ribosomal subunits.
Q: In what type of cells are nucleoli especially prominent and why?
A: Nucleoli are prominent in cells that produce a lot of protein, such as muscle and liver cells, due to high demands for ribosome production.
Q: What happens to nucleoli during cell division?
A: Nucleoli temporarily disappear during cell division and reappear in newly formed cells.
Q: What is chromatin, and how does it appear in non-dividing cells?
A: Chromatin is the material that makes up chromosomes, appearing as a loose, granular mass with a “beads-on-a-string” structure in non-dividing cells.
Q: What is a nucleosome?
A: A nucleosome consists of DNA wrapped twice around a core of eight histone proteins, forming the “beads” in the chromatin structure.
Q: What is linker DNA?
A: Linker DNA is the “string” connecting nucleosomes, maintaining the chromatin structure.
Q: What happens to chromatin during cell division?
A: Chromatin fibers condense into chromatids, and each pair of chromatids forms a chromosome during cell division.
Q: How many chromosomes do humans have, and where is this information contained?
A: Humans have 46 chromosomes in body cells, with 23 inherited from each parent; this complete set forms the genome.
Q: What is the primary function of ribosomes in the cell?
A: Ribosomes are the structures where proteins are made in the cell.
Q: What are ribosomes composed of?
A: Ribosomes are made of ribosomal RNA (rRNA) and over 50 proteins.
