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Questions and Answers
Where does the metabolism of carbohydrates, amino acids, and nucleotides occur in a cell?
Where does the metabolism of carbohydrates, amino acids, and nucleotides occur in a cell?
What is the primary function of the rough endoplasmic reticulum?
What is the primary function of the rough endoplasmic reticulum?
Where does protein synthesis occur in a cell?
Where does protein synthesis occur in a cell?
What is the function of the smooth endoplasmic reticulum?
What is the function of the smooth endoplasmic reticulum?
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What is the primary function of the Golgi apparatus?
What is the primary function of the Golgi apparatus?
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Where does fatty acid synthesis occur in a cell?
Where does fatty acid synthesis occur in a cell?
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What is the term for a protein as it is being formed by a ribosome before it folds into its active shape?
What is the term for a protein as it is being formed by a ribosome before it folds into its active shape?
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Where does the metabolism of amino acids occur in a cell?
Where does the metabolism of amino acids occur in a cell?
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What is the primary function of the nucleolus?
What is the primary function of the nucleolus?
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What is the characteristic of heterochromatin?
What is the characteristic of heterochromatin?
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What is the purpose of the central dogma of molecular biology?
What is the purpose of the central dogma of molecular biology?
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What is a characteristic of prokaryotic cells?
What is a characteristic of prokaryotic cells?
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What is the function of the nuclear envelope?
What is the function of the nuclear envelope?
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What is the function of the nucleus?
What is the function of the nucleus?
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What is the significance of plasmid DNA?
What is the significance of plasmid DNA?
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What is the difference between heterochromatin and euchromatin?
What is the difference between heterochromatin and euchromatin?
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What is the main function of the ribosome in the cell?
What is the main function of the ribosome in the cell?
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Which organelle is responsible for the degradation of intracellular proteins?
Which organelle is responsible for the degradation of intracellular proteins?
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What is the pH of the acid hydrolases found in lysosomes?
What is the pH of the acid hydrolases found in lysosomes?
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What is the function of the cristae in the mitochondria?
What is the function of the cristae in the mitochondria?
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What is the characteristic of an amphipathic molecule?
What is the characteristic of an amphipathic molecule?
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What is the main function of the endosome in the cell?
What is the main function of the endosome in the cell?
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What type of molecule can pass through the plasma membrane passively?
What type of molecule can pass through the plasma membrane passively?
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Which type of stem cell can produce all cell types necessary to give rise to a new organism?
Which type of stem cell can produce all cell types necessary to give rise to a new organism?
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What is the function of microfilaments, intermediate filaments, and microtubules in the cytoskeleton?
What is the function of microfilaments, intermediate filaments, and microtubules in the cytoskeleton?
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What is the function of the mitochondria in the cell?
What is the function of the mitochondria in the cell?
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From which face of the Golgi body do vesicles leave?
From which face of the Golgi body do vesicles leave?
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How are nucleosomes compacted to form chromosomes?
How are nucleosomes compacted to form chromosomes?
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What is the correct order of DNA organisation from the nucleus to chromosome?
What is the correct order of DNA organisation from the nucleus to chromosome?
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What is the characteristic of the DNA helix?
What is the characteristic of the DNA helix?
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What is the primary function of cytoskeleton in cellular transport?
What is the primary function of cytoskeleton in cellular transport?
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What is the difference between pluripotent and multipotent stem cells?
What is the difference between pluripotent and multipotent stem cells?
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What was Arthur Kornberg's discovery in 1957?
What was Arthur Kornberg's discovery in 1957?
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What is the function of the 5' to 3' exonuclease activity of DNA polymerase I?
What is the function of the 5' to 3' exonuclease activity of DNA polymerase I?
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During DNA replication, what is the role of the RNA primer?
During DNA replication, what is the role of the RNA primer?
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What is the outcome of the initiation stage of DNA replication?
What is the outcome of the initiation stage of DNA replication?
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During DNA replication, which enzyme is responsible for joining Okazaki fragments on the lagging strand?
During DNA replication, which enzyme is responsible for joining Okazaki fragments on the lagging strand?
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What is the direction of DNA synthesis on the leading strand?
What is the direction of DNA synthesis on the leading strand?
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What is the role of DNA polymerase's 3' to 5' exonuclease activity during DNA replication?
What is the role of DNA polymerase's 3' to 5' exonuclease activity during DNA replication?
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In which stage of the cell cycle does DNA replication occur?
In which stage of the cell cycle does DNA replication occur?
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Study Notes
Cell Components and Functions
- Cytoplasm: metabolism of carbohydrates, amino acids, and nucleotides, and fatty acid synthesis
- Cytosol: metabolism, protein synthesis (free ribosomes)
- Endoplasmic Reticulum (ER):
- Rough ER: translation of mRNA into membrane-associated proteins or for secretion out of the cell, has ribosomes attached to the outer surface
- Smooth ER: synthesis of lipids, Ca²⁺ storage, and steroid production
- Golgi Apparatus: modifies and packages proteins and lipids for delivery to other organelles or for secretion out of the cell
- Mitochondria:
- Double-membraned organelles with smooth outer and folded inner lipid bilayer membrane
- Inner membrane forms cristae, boosting surface area for ATP production
- Matrix houses Krebs cycle, mitochondrial DNA, ribosomes, and enzymes crucial for ATP generation
- Ribosome: composed of two rRNA subunits that wrap around mRNA to begin translation and protein synthesis
- Lysosomes: membrane-bound organelles containing acid hydrolases at pH 5 for intracellular digestion
- Peroxisomes: membrane-bound organelles for chemical detoxification and lipid metabolism
- Proteasome: degrades intracellular proteins
- Endosome: sorts and delivers lipid vesicles and their contents to and from the plasma membrane
- Plasma Membrane:
- Acts as a selective barrier, allowing only small, non-polar molecules to pass through passively
- Controls what enters and exits the nucleus
- Nucleus:
- Contains DNA, nucleoproteins, and RNA
- Stores DNA and coordinates cell activities such as growth, metabolism, protein synthesis, and cell division
- Nucleolus: site of ribosomal RNA (rRNA) synthesis
- Nuclear Envelope: double-layered membrane with nuclear pores allowing macromolecules to pass through
- Cytoskeleton: provides structural support, enables cell shape change and movement, and facilitates intracellular transport
DNA Structure and Replication
- Central Dogma of Molecular Biology: genetic information flows from DNA to RNA to protein
- Prokaryotic Cell: lacks a nucleus, has membrane-bound organelles, and a circular plasmid DNA genome
- Eukaryotic Cell Structure:
- Organelles are compartments with specific functions
- Nucleus contains DNA and coordinates cell activities
- DNA is found in two forms: heterochromatin (condensed, tightly packed) and euchromatin (uncondensed)
- Stem Cells:
- Totipotent: can produce all cell types necessary to give rise to a new organism
- Pluripotent: can produce nearly all cell types
- Multipotent: can produce cells of a closely related family
- Oligopotent: can produce only a few cell types of the same family
- Unipotent: can only produce one type of cell
DNA Organisation and Replication
- DNA Organisation:
- DNA is wrapped around histones to form nucleosomes
- Nucleosomes form 'beads on a string' DNA
- Solenoid structures are compacted into hierarchical loops to create chromosomes
- Arthur Kornberg's Discovery (1957): demonstrated the existence of DNA polymerase I
- DNA Polymerase I:
- Has 5' to 3' DNA polymerizing activity
- Has 3' to 5' exonuclease activity
- Has 5' to 3' exonuclease activity
- Semi-Conservative DNA Replication:
- Occurs in the Synthesis phase (S phase) of the cell cycle
- Initiation: DNA helicase untwists DNA strands, primase makes RNA primer, and DNA polymerase starts replication
- Elongation:
- Leading strand: continuous 5' to 3' strand synthesis
- Lagging strand: Okazaki fragments synthesis, joined by DNA ligase into a continuous chain
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Description
This quiz covers the different components of a cell, including cytoplasm, cytosol, endoplasmic reticulum, and golgi apparatus, and their functions in cellular metabolism and protein synthesis.
