A&P I Lecture 3: Cells, DNA, Mitosis & Cancer

93 flashcards

What did Robert Hooke observe under a microscope to describe cells? (1665): Cork
What are the three main principles of the Cell Theory?: 1. All organisms are composed of cells. 2. Cells are the smallest living things. 3. Cells arise by division of preexisting cells.
What is the main difference between a TEM and a Scanning Electron Microscope (SEM)?: TEM sees inside structures, while SEM sees the surface.
What are the two main categories of cells?: Prokaryotic cells and Eukaryotic cells.
What do all cells have in common?: They are surrounded by a plasma membrane, contain cytosol, genes (DNA), and ribosomes.
What distinguishes Eukaryotic cells from Prokaryotic cells?: Eukaryotic cells contain a nucleus and organelles.
What is the function of ribosomes?: They synthesize proteins from RNA.
What is the role of the Golgi apparatus?: It modifies proteins and sends them to their destinations.
What is the function of lysosomes?: They break down large molecules and help destroy viruses and bacteria.
What do vacuoles do in plant cells?: Store materials such as water, nutrients, and pigments.
What is the primary function of mitochondria?: Perform cellular respiration and produce ATP.
What do chloroplasts do?: Convert light energy into chemical energy through photosynthesis.
What is the Endosymbiosis Theory?: It suggests that mitochondria and chloroplasts were once independent prokaryotic organisms.
What evidence supports the Endosymbiosis Theory?: Both organelles have two membranes, their own circular DNA, and divide by fission.
What is the plasma membrane's primary function?: To separate the living cell from its nonliving surroundings and regulate entry and exit of substances.
What are phospholipids?: Molecules that make up the plasma membrane, consisting of hydrophilic heads and hydrophobic tails.
What structure do phospholipids form in the plasma membrane?: A phospholipid bilayer.
What is the function of the smooth endoplasmic reticulum?: Produces lipids and detoxifies certain drugs.
What is the function of the rough endoplasmic reticulum?: Contains ribosomes that produce membrane and secretory proteins.
What is cytosol?: The thick, jelly-like fluid contained within cells.
What is the function of the nuclear envelope?: It encloses the nucleus and separates it from the cytoplasm.
What are the two types of ribosomes?: Free ribosomes and bound ribosomes.
What is the function of chloroplasts in plant cells?: To perform photosynthesis and convert light energy into chemical energy.
What forms the plasma membrane?: A phospholipid bilayer with hydrophilic heads facing outward and hydrophobic tails inward.
What is the characteristic structure of the plasma membrane?: It is considered a fluid mosaic, allowing molecules to move freely.
What does selectively permeable mean in the context of plasma membranes?: It allows some materials to pass while restricting others.
What are the three types of membrane permeability?: Freely permeable, selectively permeable, and impermeable.
What is diffusion?: The random movement of molecules resulting in even distribution, occurring down concentration gradients.
What factors influence diffusion?: Distance, molecule size, temperature, gradient size, and electrical forces.
What is osmosis?: The net diffusion of water across a membrane driven by solute concentration differences.
What is tonicity?: The effect of a solution on cell volume, categorized as isotonic, hypotonic, or hypertonic.
What is carrier-mediated transport?: Transport of hydrophilic or large molecules, which can be passive or active.
What are the types of vesicular transport?: Endocytosis (including receptor-mediated, pinocytosis, and phagocytosis) and exocytosis.
What is the function of the nucleus?: It contains DNA and is separated from the cytoplasm by the nuclear envelope.
What is chromatin?: A long stretch of DNA molecule with proteins that help package DNA into chromosomes.
Who contributed to the discovery of DNA structure?: Rosalind Franklin, James Watson, and Francis Crick.
What did Rosalind Franklin's Photograph 51 reveal?: It showed that DNA has a helical structure.
What are the components of a nucleotide?: Phosphate group, deoxyribose sugar, and nitrogenous bases.
What are the nitrogenous bases in DNA?: Adenine (A), Guanine (G), Cytosine (C), and Thymine (T).
What is the significance of the antiparallel strands in DNA?: One strand runs from 5' to 3' and the other from 3' to 5', allowing for complementary base pairing.
What is the Central Dogma of molecular biology?: It describes the flow of genetic information from DNA to RNA to protein.
What occurs during transcription?: The genetic code in DNA is copied into messenger RNA (mRNA).
What are the three steps of transcription?: Initiation, elongation, and termination.
What happens during the initiation phase of transcription?: RNA polymerase binds to the promoter region of the gene.
What occurs during elongation in transcription?: RNA polymerase synthesizes a complementary strand of RNA in the 5' to 3' direction.
What is the termination step in transcription?: Transcription ends when RNA polymerase reaches a terminator sequence in the DNA.
What is the role of ATP in active transport?: ATP is required to move substances against their concentration gradient.
What is facilitated diffusion?: A type of passive transport that uses carrier proteins to help move substances across the membrane.
What is the difference between pinocytosis and phagocytosis?: Pinocytosis is 'cell drinking' of fluids, while phagocytosis is 'cell eating' of larger particles.
What is osmotic pressure?: The force of water movement due to solute concentration differences.
What does hydrostatic pressure refer to in osmosis?: The pressure needed to stop osmosis.
What is the process that ends transcription?: Transcription ends when RNA polymerase reaches a terminator sequence in the DNA.
What processing does mRNA undergo in eukaryotes before leaving the nucleus?: mRNA undergoes capping, splicing, and polyadenylation.
What is the start codon for translation?: AUG (adenine-uracil-guanine).
What happens during the initiation phase of translation?: The ribosome assembles around the mRNA at the start codon, and a tRNA molecule binds to the start codon.
What direction does the ribosome move along the mRNA during elongation?: The ribosome moves in the 5' to 3' direction.
What do codons specify during translation?: Each codon specifies a particular amino acid.
What is the role of tRNA in translation?: tRNA molecules bring the appropriate amino acids to the ribosome.
What is formed when amino acids are linked together by the ribosome?: A growing polypeptide chain.
What signals the termination of translation?: A stop codon (UAA, UAG, or UGA) is reached.
What happens to the ribosome and mRNA at the end of translation?: The ribosome disassembles, and the mRNA is released.
What is the first step of the central dogma of molecular biology?: Transcription (DNA ’ mRNA).
What is the second step of the central dogma of molecular biology?: Translation (mRNA ’ Protein).
What are the three stages of the eukaryotic cell cycle?: Interphase, M phase, and C phase (cytokinesis).
What is the purpose of mitosis?: Mitosis is the cell division of nonreproductive cells (somatic cells).
What is meiosis?: Meiosis is the division of sexually reproductive cells (germ cells).
What are the phases of interphase?: G1 phase (first growth), S phase (synthesis), and G2 phase (second growth).
What occurs during the S phase of interphase?: DNA replication occurs, producing two copies for each chromosome.
What is cytokinesis?: The division of cells resulting in two identical daughter cells.
What is the G1 phase known as?: The gap phase or first growth phase.
How long do most cells spend in the G1 phase?: Most cells spend most of their life in the G1 phase.
What are homologous chromosomes?: A pair of chromosomes, one from each parent.
What are sister chromatids?: A pair of identical duplicated chromatids bound together at the centromere.
What shape do sister chromatids appear as?: An 'X' shape.
What is the composition of chromatin?: 40% DNA and 60% protein.
What role do histones play in DNA structure?: Histones are positively charged proteins that DNA binds to, neutralizing its negative charge.
During which phase is DNA not usually wound into chromosomes?: Interphase.
What are the four phases of mitosis?: Prophase, Metaphase, Anaphase, Telophase.
What happens during prophase?: Chromosomes become visible, the nuclear envelope breaks down, and centrioles form.
What occurs during metaphase?: Sister chromatids align along the equatorial plane of the cell.
What happens during anaphase?: Centromeres break apart, and sister chromatids are pulled to opposite ends of the cell.
What occurs during telophase?: Sister chromatids are at opposite ends, the spindle disassembles, and the nuclear envelope reforms.
What is a malignant tumor?: A tumor that becomes invasive and can spread to other areas of the body.
What is metastasis?: The process by which malignant tumors spread to other areas of the body.
What causes cancer at the cellular level?: Uncontrolled growth due to disruptions in the regulation of the cell cycle.
What are proto-oncogenes?: Proteins that stimulate the cell cycle.
What are tumor suppressor genes?: Proteins that act to suppress the cell cycle.
What is the leading cause of cancer-related deaths in the United States?: Lung cancer.
What are carcinogens?: Chemicals associated with the development of cancer.
What is the function of the p53 protein?: A tumor suppressor crucial for regulating the cell cycle.
What is vaping?: The act of inhaling vapor produced by heating a nicotine solution, typically in e-cigarettes.
What is a common chemical found in e-cigarettes?: Propylene glycol.
What is Juul?: A popular type of e-cigarette that contains more nicotine than other e-cigarettes.