Unit I Study Guide 1A For eukaryotes what are the functions of replication transcription and translation and where do they occur Transcription RNA Synthesis Replication Translation Function DNA makes copies of itself because cells divide for an organism to grow or reproduce and every new cell needs a DNA is copied into a strand of mRNA and mRNA is read and copied into a protein to carry out some function for Protein Synthesis Ribosomes read RNA and use the sequence to create a protein by combining various amino acids 1B What is a gene Where it Occurs Nucleus Nucleus Cytoplasm Gene A discrete unit of hereditary information consisting of a specific nucleotide sequence in DNA 1C What is a chromosome Chromosome A cellular structure carrying genetic material found in the nucleus of eukaryotic cells o Consists of one long DNA molecule and associated proteins 1D Genetic Code a Codon that codes for 1 amino acid Triplet of 3 mRNA bases Anticodons are the corresponding triplet sequence on tRNA 1E Mutation change in the amino acid sequence silent mutation no amino acid change because of the wobble effect missense mutation a change in the 2nd pair of the sequence and results in an amino acid change o Both silent and missense are nucleotide substitutions Nonsense mutation early or no stop signal occur o Due to a frame shift o This is called a nucleotide indel a frame shift mutation by altering codon reading frame 1F mutations allows for the evolutionary process in organisms and helps them 1 adapt to changing environements 1G Chromatin DNA and protein that makes up contents of the nucleus Euchromatin loosely coiled DNA that is transcriptionally active Heterochromatin tightly packed inactive Chromatin functions for gene expression repression and DNA transcription 2A What is meant by gene expression Gene Expression The conversion of the information from the gene into mRNA via transcription and then to protein via translation resulting in the phenotypic manifestation of the gene 2B What is meant by gene regulation Gene Regulation A process in which a cell determines which genes it will express and when 2C Why is gene regulation important necessary to cells organisms Organisms do not want to express all of their genes all of the time Multicellular organisms very complex Main reason gene regulation is necessary cell specialization Each cell type differentiates by activating a different subset of genes 2 Because of the multitude of cell types the regulation of gene expression required to bring about such differentiation is necessarily complex Valuable to cell function o As a cell goes through its life it has different needs and functions can be addressed by gene regulation o Cells can adapt to environmental changes by activating new genes 3 List the different types of proteins describe their function in a cell organism and provide an example of each Enzymes Catalyze reactions o Ex DNA polymerase Structural Proteins Support o Ex Keratin collagen Transport Proteins Transport other molecules Hormones Coordinate cell organism activities o Ex Hemoglobin o Ex Insulin Receptors Respond to bind to chemical stimuli o Ex Olfactory receptors G proteins Defense Proteins Defend o Ex Antibodies Contractile Motor Proteins Help with movement Storage Proteins Store amino acid reserves o Ex Actin myosin o Ex Ovalbumin 4A Broadly and in general terms how and why do cells communicate Cells communicate by sending each other signals that can instruct them to turn certain genes on or off or to bring about some other cellular response Mechanisms of cell communication guide development Cell to cell communication is necessary to coordinate cell movement and cell differentiation during development 4B List and describe the three stages of cell signaling 1 Reception A signal molecule is received by a receptor molecule on cell membrane or inside cell 2 Transduction A stepwise series of chemical reactions initiated by an activated receptor molecule to bring about a specific cellular response 3 Response The end result of a specific signaling pathway 3 5A Define genomic equivalence All the somatic cells in an organism say the human body are genomically equivalent why What makes them different 4 Genomic Equivalence All the different cell types in an organism have identical genomes same DNA but they express different genes o Different cells express different genes makes them different 5B What is meant by cell potency A cell s potency describes its ability to differentiate 5C Distinguish between and give an example of multipotent pluripotent and totipotent cells Totipotency The potential of a cell to differentiate into an entire organism because no genes are irreversibly turned off o Potential to become an individual o Ex Early embryonic stem cells Pluripotency Cells can give rise to many but not all parts of an organism o Potential to become any cell but not an organism o Ex Later embryonic stem cells Multipotency Cells are already differentiated with limited potential o Ex Adult stem cells 5D What is a stem cell Stem Cells Relatively undifferentiated cells that can be induced to differentiate 5E Distinguish between embryonic and adult stem cells Embryonic Stem Cells Can be totipotent and develop into a new individual when obtained from very early embryos Can be pluripotent and differentiate into ANY cell type Adult Stem Cells Multipotent Can differentiate into some but not all cell types Ex Bone marrow stem cells red white blood 5F Why are stem cells of great research interest Therapeutic Cloning Transplant a nucleus into an enucleated egg to get an early embryo then use the pluripotent cells to grow different types of cells for research 5 Stem cells have many potential therapeutic uses can be used to replace damaged diseased tissues and organs 6 5G Define determination induction and what are cytoplasmic determinants CDs and why are they important in embryonic development Determination A molecular process by which a cell differentiates into a particular cell type by expressing a unique set of genes o Relies on cell signaling gene regulation to make cell specific proteins Induction Cells can be induced to differentiate later in life via cell cell signaling molecular signals from one cell are received by a nearby cell and these set up signal transduction pathways that change gene expression Cytoplasmic Determinant CD A maternal substance such as a protein or RNA that when placed into an egg influences the course of early development
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