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 (142 cards)
1
Q
Q: What are the two components of the cytoplasm?
A
A: The cytoplasm consists of the cytosol and organelles.
2
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Q: What is the cytosol?
A
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.
3
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Q: What percentage of the cytosol is water?
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A: The cytosol is 75-90% water.
4
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Q: What key process occurs in the cytosol?
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A: Glycolysis, the breakdown of glucose to produce ATP, occurs in the cytosol.
5
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Q: What is the cytoskeleton?
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A: The cytoskeleton is a network of protein filaments in the cytosol that maintains cell shape and supports organelles.
6
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Q: What are the components of the cytoskeleton?
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A: The cytoskeleton is composed of microfilaments, intermediate filaments, and microtubules.
7
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Q: What are microfilaments, and what do they do?
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A: Microfilaments are the thinnest components, made of actin and myosin, providing mechanical support and enabling movement like muscle contraction and cell division.
8
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Q: What roles do intermediate filaments play in the cell?
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A: Intermediate filaments provide structural reinforcement, hold organelles in place, and help shape the cell.
9
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Q: What are microtubules, and what are their primary functions?
A
A: Microtubules are cylindrical filaments made of tubulin, providing support, structure, and enabling transportation within the cell.
10
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Q: What are organelles?
A
A: Organelles are specialized structures within cells that have unique shapes and functions to support growth, maintenance, and reproduction.
11
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Q: Why do different cellular reactions occur in separate organelles?
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A: To prevent interference between reactions and to compartmentalize processes, allowing for specific conditions and enzymes to be maintained.
12
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Q: What determines the type and number of organelles in a cell?
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A: The cell’s specific role or function determines the type and number of organelles it contains.
13
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Q: How do organelles contribute to homeostasis within a cell?
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A: While they have distinct functions, organelles work together to maintain balance and proper functioning within the cell.
14
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Q: Why is the nucleus often discussed separately from other organelles?
A
A: Because the nucleus controls the cell’s activities and contains the genetic material.
15
Q
Q: What is a key feature of organelles in terms of cell processes?
A
A: Each organelle contains specific enzymes for their tasks, acting as compartments for certain processes.
16
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Q: How do organelles contribute to cellular efficiency?
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A: By compartmentalizing processes, organelles allow for specialized environments and efficient reaction conditions tailored to specific tasks.
17
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Q: What is the primary function of the cytoskeleton?
A
A: The cytoskeleton helps determine cell shape and organizes organelles, aiding in movement, absorption, and support.
18
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Q: What are the three types of filaments in the cytoskeleton?
A
A: Microfilaments, intermediate filaments, and microtubules.
19
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Q: What are microfilaments made of, and what is their function?
A
A: Microfilaments are made of actin and myosin; they aid in movement such as muscle contraction and cell division and provide support.
20
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Q: Where are microfilaments primarily located, and what do they support?
A
A: They are found at the cell’s edge and support cell extensions like microvilli for absorption.
21
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Q: What is the role of intermediate filaments in the cell?
A
A: Intermediate filaments provide strength, hold organelles like the nucleus in place, and help cells attach to each other.
22
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Q: How are microtubules formed, and what are their functions?
A
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.
23
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Q: What role do microtubules play in cellular movement?
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A: They assist in the movement of organelles, chromosomes during cell division, and structures like cilia and flagella to facilitate locomotion.
24
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Q: What are cilia?
A
A: Cilia are hairlike projections that extend from the cell surface, helping move fluids along the cell surface.
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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.
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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.
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Q: What role do microtubules play in cilia?
A: Microtubules are structural components of cilia,.
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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.
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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.
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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.
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Q: What are flagella?
A: Flagella are long, whip-like structures similar to cilia but much longer, used to move entire cells.
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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.
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Q: How does a flagellum move the cell?
A: A flagellum moves in a wave-like pattern to propel the cell forward.
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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.
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Q: Describe the motion of a flagellum.
A: The flagellum moves by wiggling in a wave-like pattern to push the cell forward.
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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.
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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.
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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.
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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.
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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.
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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.
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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.
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Q: What are the hereditary units within the nucleus called?
A: The hereditary units are called genes.
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Q: How are genes organized in the nucleus?
A: Genes are arranged along chromosomes.
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Q: What are chromosomes composed of?
A: Chromosomes are made up of DNA and a histone protein complex.
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Q: What is the role of histone proteins?
A: Histone proteins provide structural support for DNA, helping to organize it into chromatin.
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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.
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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.
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Q: What happens to nucleoli during cell division?
A: Nucleoli temporarily disappear during cell division and reappear in newly formed cells.
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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.
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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.
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Q: What is linker DNA?
A: Linker DNA is the "string" connecting nucleosomes, maintaining the chromatin structure.
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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.
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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.
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Q: What is the primary function of ribosomes in the cell?
A: Ribosomes are the structures where proteins are made in the cell.
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Q: What are ribosomes composed of?
A: Ribosomes are made of ribosomal RNA (rRNA) and over 50 proteins.
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Q: Describe the structure of a ribosome.
A: Each ribosome consists of two subunits: a large one and a smaller one.
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Q: Where are ribosomal subunits made?
A: Ribosomal subunits are made in the nucleolus inside the nucleus.
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Q: How do ribosomal subunits become functional ribosomes?
A: The subunits leave the nucleus separately and combine in the cytoplasm to become functional ribosomes.
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Q: What are attached ribosomes, and what do they do?
A: Attached ribosomes are connected to the nuclear membrane and the endoplasmic reticulum, making proteins for organelles, the cell membrane, or export out of the cell.
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Q: What are free ribosomes, and where do they operate?
A: Free ribosomes float in the cytoplasm and produce proteins that will be used inside the cell.
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Q: What are mitochondrial ribosomes, and what is their role?
A: Mitochondrial ribosomes are found in mitochondria and make proteins for the mitochondria itself.
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Q: Where can ribosomes be found in the cell?
A: Ribosomes can be found in nucleoli, free in the cytosol, and on the rough ER.
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Q: How do ribosomes assemble proteins?
A: Ribosomes use directions in messenger RNA (mRNA) to assemble amino acids into proteins, as specified by the genetic code (DNA).
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Q: Why are proteins essential for cells?
Hint - Mnemonic: "Happy Tigers Can Hunt Many Energetic Tigers."
Homeostasis maintenance
Trait determination
Cellular structure formation
Hormone and antibody functions
Muscle component formation
Enzyme activity (regulating chemical reactions)
Transport of materials in the blood
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Q: What is the complete set of proteins in an organism called?
A: The complete set of proteins is called the proteome.
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Q: What is the process of transcription?
A: Transcription is the process of copying DNA into RNA.
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Q: What does gene expression involve?
A: Gene expression involves using DNA to make proteins.
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Q: What occurs during translation?
A: During translation, RNA guides the assembly of amino acids into proteins at the ribosome.
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Q: Where does transcription occur in the cell?
A: Transcription occurs in the nucleus.
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Q: What is the purpose of transcription?
A: The purpose of transcription is to copy genetic information from DNA onto messenger RNA (mRNA) to direct protein synthesis.
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Q: What is a promoter in DNA?
A: A promoter is the DNA sequence where transcription begins, signaling RNA polymerase to start making mRNA.
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Q: What is a terminator in DNA?
A: A terminator is the DNA sequence where transcription ends, telling RNA polymerase to stop and release the mRNA.
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Q: What enzyme is responsible for transcription?
A: RNA polymerase is responsible for transcription.
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Q: Which strand of DNA is used during transcription?
A: Only one strand of DNA, the template strand, is used to make RNA.
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Q: During transcription, what base pairs with adenine in RNA?
A: In RNA, uracil (U) pairs with adenine (A).
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Q: What are exons and introns?
A: Exons are sequences that code for proteins, while introns are non-coding sequences located between exons.
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Q: What happens to pre-mRNA after transcription?
A: The introns are removed, and the exons are spliced together by snRNPs to form functional mRNA, which then leaves the nucleus for protein synthesis.
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Q: What is the role of RNA polymerase during transcription?
A: RNA polymerase binds to the promoter, reads the DNA template, and creates a complementary RNA strand until it reaches the terminator.
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Q: What enzyme catalyzes transcription, and where does it occur?
A: RNA polymerase; occurs in the nucleus.
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Q: What are the three types of RNA produced during transcription, and their functions?
A:
mRNA: Directs protein synthesis.
rRNA: Forms ribosomes.
tRNA: Transfers amino acids during protein synthesis.
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Q: How does the DNA template AGCT convert into mRNA?
A: It becomes UCGA in the mRNA.
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Q: What is the role of the promoter and terminator in transcription?
A: The promoter is where transcription begins, and the terminator is where it ends.
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Q: What are introns and exons, and how are they processed?
A: Introns are non-coding regions removed from pre-mRNA, while exons are coding regions spliced together to form functional mRNA.
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Q: What base does adenine pair with in RNA, and what replaces thymine?
A: Adenine pairs with uracil in RNA, and uracil replaces thymine.
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Q: Where does translation take place?
A: Translation occurs in the cytoplasm.
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Q: What is the role of mRNA in translation?
A: mRNA carries the genetic code for specifying the amino acid sequence of a protein.
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Q: What initiates the translation process?
A: The ribosome assembling around the target mRNA and the first tRNA attaching to the start codon.
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Q: How does the translation process conclude?
A: Translation ends when a stop codon is reached, prompting the ribosome to release the completed protein.
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Q: What does tRNA do during translation?
A: tRNA matches amino acids to their corresponding mRNA codons and facilitates their addition to the growing polypeptide chain.
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Q: Describe the function of the ribosome's small and large subunits.
A: The small subunit binds to mRNA, while the large subunit has three sites (P, A, E) for tRNA binding.
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Q: What are the functions of the P, A, and E sites on the ribosome?
P Site: Holds the tRNA with the growing protein chain.
A Site: Holds the tRNA with the next amino acid to be added.
E Site: Releases tRNA after its amino acid has been added.
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Q: What are post-translational modifications?
A: They are changes that proteins undergo after synthesis during translation, crucial for their final structure, function, and cellular localization.
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Q: How can post-translational modifications alter a protein's activity?
A: By enabling or disabling specific functional sites, thus impacting its role within the cell.
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Q: Why are these modifications important for protein localization?
A: They direct proteins to their proper cellular compartments, ensuring they function where needed.
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Q: How do post-translational modifications affect protein interactions?
A: They can modulate the affinity or specificity for interacting with other molecules.
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Q: What role do these modifications play in protein stability?
A: They can stabilize proteins for active use or mark them for degradation to regulate lifespan.
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Q: What is the importance of protein degradation?
A: It breaks down damaged or unneeded proteins, maintaining cellular homeostasis.
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Q: How do post-translational modifications relate to cellular homeostasis?
A: They ensure proper protein functionality and timely degradation, balancing cellular processes.
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Q: What connects the ER to the rest of the cell?
A: The ER connects to the nuclear envelope and spreads throughout the cytoplasm.
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Q: What differentiates rough ER from smooth ER structurally?
A: Rough ER has ribosomes attached to its surface, while smooth ER does not.
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Q: What are the primary functions of the rough ER?
A: Protein synthesis, lipid production, and protein processing and sorting.
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Q: What are the primary functions of the smooth ER?
A: Lipid synthesis, detoxification, carbohydrate metabolism, and calcium storage.
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Q: What specific types of lipids are produced by the smooth ER?
A: Fatty acids, and steroids such as estrogen and testosterone.
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Q: How does the rough ER contribute to protein secretion?
A: It processes and sorts proteins, preparing them for integration in the plasma membrane or for secretion via exocytosis.
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Q: Why is calcium storage in the smooth ER important?
A: Stored calcium ions are crucial for muscle contraction.
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Q: In what cellular processes is the smooth ER involved through detoxification?
A: Detoxifying drugs and harmful substances.
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Q: What structural feature distinguishes the rough ER from the smooth ER?
A: The rough ER has ribosomes on its surface, while the smooth ER does not.
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Q: What type of proteins does the rough ER primarily produce?
A: Membrane and cytosolic proteins.
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Q: Through which cellular organelle do proteins synthesized by the rough ER typically pass for further processing?
A: The Golgi complex.
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Q: Name two functions of the smooth ER related to lipid processing.
A: Synthesis of fatty acids and steroid hormones such as testosterone and estrogen.
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Q: How does the smooth ER contribute to glucose metabolism?
A: It processes glucose-6-phosphate, aiding in carbohydrate metabolism.
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Q: What specialized form of smooth ER is involved in muscle contraction?
A: The sarcoplasmic reticulum.
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Q: Which cellular process is smooth ER primarily not involved in due to its lack of ribosomes?
A: Protein synthesis.
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Q: How are the rough and smooth ER structures related to each other?
A: The smooth ER extends from the rough ER.
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Q: What are the structural components of the Golgi complex?
A: 3-20 flattened sacs called saccules.
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Q: How does the Golgi complex receive proteins, and from where?
A: Proteins are received at the entry (cis) face from the rough ER.
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Q: What happens to proteins in the intermediate saccules of the Golgi complex?
A: They are modified into glycoproteins and lipoproteins.
118
Q: Name the three types of vesicles formed by the Golgi complex and their functions.
Secretory vesicles: Carry proteins outside the cell via exocytosis.
Membrane vesicles: Deliver new molecules to the plasma membrane.
Transport vesicles: Deliver proteins to organelles like lysosomes.
119
Q: What are the primary functions of lysosomes?
Digesting substances from outside the cell, recycling worn-out organelles (autophagy), and potentially destroying the entire cell (autolysis).
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Q: How many different enzymes do lysosomes contain, and what is their purpose?
A: About 60 different digestive and hydrolytic enzymes for breaking down biological molecules.
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Q: What is autophagy, and how does it differ from autolysis?
A: Autophagy is the digestion of worn-out organelles, while autolysis is the destruction of the entire cell.
122
Q: although similar in shape, how do peroxisomes differ from lysosomes?
A: They are smaller and contain enzymes that oxidize organic substances and detoxify harmful compounds.
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Q: What role does catalase play in peroxisomes?
A: Catalase breaks down hydrogen peroxide (H2O2) into water and oxygen, preventing cellular damage.
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Q: How can peroxisomes replicate?
A: By enlarging and dividing or forming anew from cellular components.
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Q: What is the primary function of proteasomes?
A: To degrade unneeded, damaged, or faulty proteins into small peptides and amino acids.
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Q: Where are proteasomes located?
A: In the cytosol and the nucleus.
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Q: How do proteasomes contribute to cellular homeostasis?
A: By regulating metabolic pathways through protein degradation, aiding in negative feedback.
128
Q: What diseases are associated with malfunctioning proteasomes, and why is this significant?
A: Parkinson's and Alzheimer's, due to the accumulation of abnormal proteins; understanding this process may lead to treatment strategies.
129
Q: What are the structures called that destroy unneeded, damaged, or faulty proteins by cutting them into smaller peptides?
A: Proteasomes
130
Q: What happens to the smaller peptides produced by proteasomes?
A: They can be broken down by proteases into individual amino acids.
131
Q: What is the final use of the amino acids that result from the breakdown of peptides?
A: They can be recycled into more functional, healthy proteins.
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Barrel-shaped structures that destroy unneeded, damaged, or faulty proteins by cutting long proteins into smaller peptides
Proteasomes
133
Q: What is the primary function of mitochondria?
A: They generate most of the cell's ATP through aerobic respiration.
134
Q: How does the quantity of mitochondria vary in different types of cells?
A: The number of mitochondria depends on the cell's activity level, with more present in active cells like muscle, liver, and kidney cells.
135
Q: How does regular exercise affect mitochondria in muscle cells?
A: It increases the number of mitochondria, improving the efficiency of energy production.
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Q: What is the structure of mitochondria?
A: Mitochondria have an outer and inner membrane, with the inner membrane forming folds called cristae. They also have a central space known as the mitochondrial matrix.
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Q: What role do mitochondria play in apoptosis?
A: They initiate programmed cell death by releasing chemicals like cytochrome c, which triggers cell death pathways.
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Q: How do mitochondria replicate?
A: They can self-replicate during periods of increased energy demand or when cells divide. They also contain their own circular DNA.
139
Q: How is mitochondrial DNA inherited?
A: It is inherited only from the mother, allowing for tracing of maternal lineage through mitochondrial DNA.
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Q: What structures are contained within the mitochondrial matrix?
A: It contains ribosomes and small, circular DNA molecules known as mitochondrial DNA (mtDNA).
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Q: What is the function of the cristae in mitochondria?
A: ATP is synthesized by enzymes on the cristae from energy extracted from carbohydrates, lipids, proteins, and alcohol.
