FAU Life Science Exam 4
Terms in this set (88)
-Macromolecules made of repeating amino acid subunits
-Examples: muscle contraction, catalyze chemical reactions, fight infection
-Building blocks of proteins
-20 different amino acids
-All have the same basic core structure.
-Each also has a unique chemical side group
What do amino acids do?
-Bond together to form linear chains
-Chains fold into 3-D protein based on amino acid sequence.
-Amino acid sequence determines shape and function of a protein.
-Changing an amino acid in protein changes 3-D shape of the protein and its function!!
-A sequence of DNA that contains the information to make at least one protein.
-Genes are found on chromosomes.
-Each chromosome carries a unique set of genes.
-Synthesis of a protein from a gene
Process of converting genetic information into protein (DNA RNA Protein)
-Two main steps: transcription and translation.
-Transcription occurs in nucleus of eukaryotic cells and cytoplasm of prokaryotic cells.
-Translation occurs on ribosomes in cytoplasm.
-Alternative versions of the same gene
-Have different nucleotide sequences
-Different alleles influence protein function
The 2 parts of genes?
-Regulatory sequences- determine when and how much protein a gene makes.
-Coding sequences- determine the amino acid sequence of the protein.
-messanger RNA is synthesized from genes
-RNA polymerase binds to the regulatory sequence of the gene. The DNA strands unwind and expose the coding sequence of the gene.
-RNA polymerase copies a strand of DNA into a complementary strand of mRNA by "reading" the gene coding sequence.
-Complementary mRNA forms from a DNA template according to the rules of base pairing, except that in RNA, adenine (A) pairs with uracil (U).
-mRNA strand is formed, detaches from DNA and DNA reforms its double-helix.
-Completed mRNA molecule leaves nucleus.
-Gene can be used again for transcription.
-mRNA molecules are used to assemble the corresponding amino acid sequence of the protein.
-mRNA molecule associates with a ribosome.
-Ribosome moves along the mRNA, "reading" it in groups of three nucleotides = codons.
-A codon specifies a specific amino acid.
-Transfer RNA (tRNA) carries an amino acid to the mRNA and ribosome by using its anticodon to find a matching mRNA codon.
-When correct tRNA is in place, the specified amino acid is added to the growing chain.
-Ribosome moves on to the next codon.
-Completed amino acid chain detaches from the ribosome and folds into its 3-D shape.
The Genetic Code
-Set of rules relating specific mRNA codons with specific amino acids.
-It is both redundant and universal.
-Process of assembling new "hybrid" genes
-Results in novel combinations of regulatory and coding sequences.
-Recombinant gene = a new combination of DNA segments (often from two species).
Making transgenic organisms/ genetically modified organisms (GMO)
-Use needle to inject the recombinant gene into a fertilized single-cell goat embryo
-Transgenic embryo is implanted into mother
-Embryo grows and inserted gene is replicated and passed on to every cell
-Harvest transgenic milk and purify protein
-Transgenic crops are modified to contain genes for natural pesticides.
-Transgenic animals are used to research a gene's function or produce marketable products.
Genetically modified animals
-Animals that have been genetically altered are called transgenic organisms.
-Isolate gene of interest from human chromosome.
-Insert it into animal embryo.
-Gene must be a hybrid so human protein is expressed in animal.
-Helps prevent blood clots (thrombosis)
-Gene is on chromosome 1
-Protein made by liver cells and released into bloodstream.
-Having one or two copies of defective antithrombin gene.
-Usually only one allele makes a functional antithrombin protein.
-Take medication when clot risks are high.
Antithrombin recombinant gene
-Use regulatory sequence of a milk gene
-Use coding sequence of antithrombin
-Hybrid gene expresses antithrombin only in the mammary cells
-Using genetically modified animals to make pharmaceutical drugs.
-Human protein (antithrombin) is extracted from the goats' milk .
Advantages of pharming
-Makes complex human proteins
-Makes large amount of protein
What are stem cells?
-Immature cells that can divide repeatedly and give rise to more specialized cell types
-Help regenerate tissues
an organized group of cells that work together to carry out a function
-An organized group of tissues that work together to carry out a function
-Often multiple cell types and layers of tissues
-Organs work together to form
the body's systems
Growing your own organs
1. A biopsy is taken from the organ
2. Stem cells from the tissues are grown (cells divide)
3. Cells are placed onto a scaffold in the shape of the organ and grown.
4. Surgeons implant the newly grown organ into the patient's body.
Adult stem cells
-Help heal tissue damage.
-Cells must go through a process of specialization to replace specific cell types.
-Cellular differentiation = cell specializes to carry out a specific function.
-Differential gene expression = some genes are turned on and others are turned off to achieve cellular differentiation.
-Using stem cells to regenerate damaged or diseased tissues
1. therapeutic drugs stimulate stem cells within the body to repair damaged tissue
2. stem cells are stimulated outside the body and then injected to repair damaged tissue
3. biodegradable materials are used to support regeneration of tissues within the body
4. biodegradable scaffolds can be used to generate tissues and organs outside the body, which are then transplanted to replace damaged tissue
Stem cells are not equal
-Some embryonic stem cells can differentiate into any of the body's cell types = totipotent. These are isolated before the blastocyst stage.
-Some embryonic stem cells can differentiate into nearly any of the body's cell type = pluripotent. These are isolated at the blastocyst stage.
-Adult stem cells can only differentiate into a few cell types = multipotent. These are isolated from adult tissues.
obtaining embryonic stem cells
1. From discarded human embryos from fertility clinics
2. Through cloning or somatic cell nuclear transfer
3. By engineering embryonic-like stem cells
-Adding a few genes to differentiated human cells = induced pluripotent stem cells
Technique using 3-D computer graphics and differentiated cells to make organs.
-a group of organisms of the same species living together in the same geographic area.
-An entire population can change (evolve) when some traits are favored over others.
-For example, bacteria developing a drug-resistant trait.
how populations evolve
-A genetically diverse population has different allele frequencies.
-The environment favors some alleles over others.
-Allele frequency changes over time
-an organism's ability to survive and reproduce in a particular environment.
-Higher fitness = increased likelihood of alleles being passed to next generation.
-For example, alleles that confer resistance to antibiotics increase the fitness of bacteria.
-An organism's alleles, or genotype, determine its phenotype.
-Differential survival & reproduction of individuals within a population in response to environmental pressure.
-Advantageous traits become more common and population becomes better suited, or adapted, to environment.
-Populations (not individuals) evolve.
-Populations experience changes in allele frequencies over time.
-predominant phenotypes near one end of the spectrum
-occurs when a single phenotype predominates in a particular environment
-predominant phenotypes near middle of the spectrum
-occurs when phenotypes at each end of the spectrum are less suited to the environment than organisms in the middle of the phenotypic range
-predominant phenotypes are at both ends of the spectrum
-typically occurs in a "patchy" environment, in which extremes of the phenotypic range do better than the middle range individuals
Staphylococcus aureus/ staph
-special bacterium that can cause pimples, boils, and wound infections in healthy people.
-can be passed from person to person by direct contact with contaminated skin or by transfer of the bacteria via contaminated objects or surfaces.
Methicillin-resistant Staphylococcus aureus (MRSA)
-An infectious bacterium.
Developed resistance to antibiotics.
-Kills 20,000+ people in the US each year.
-Adversely affects people with -weakened immune system (e.g. people with the flu).
-Chemicals that kill bacteria.
-Interfere with function of essential bacterial cell structures.
-Bacteria acquire random mutations when DNA replicates during asexual reproduction
-can result in: random mutation or gene transfer
-One parental cell divides into two daughter cells.
-In an environment with antibiotics present, bacteria emerge that survive antibiotics
-Control resistance by changing practices that enable resistant strains to thrive.
-Wash hands, use hand sanitizers, stop misuse of antibiotics.
estimated age of Earth
4.5 billion years
amount of radioactivity present in a rock is used as a geologic clock
unstable form of an element that decays into another element by emitting energetic particles (radiation)
-the time it takes for half the isotope in a sample to break down
-Used to determine the age of the materials in which they're found.
When and how did life begin?
-3 billion years ago
-Harold Urey and Stanley Miller:
*Replicated the chemical environment of early Earth in the lab.
*Their experiment yielded new organic molecules, including amino acids
*Showed that it was possible to create molecules of life from inorganic materials.
geologic timescale of earth
-Produced using the fossil record
-Earth's geography and climate have gone through dramatic changes.
What was life like millions of years ago?
-Oldest known fossils date 3.5 billion years ago
-Atmosphere lacked oxygen
-Unicellular prokaryotes that used other gases as a fuel source
-Emergence of unicellular photosynthetic organisms 3.0 to 2.5 billion years ago
-Oxygen began to accumulate in the atmosphere
-First multicellular eukaryotic organisms: green algae, 1.2 billion years ago
-Marine invertebrates arrived 600 mya
-Diverse animal world in Cambrian explosion
-Land colonized by primitive plants 450 mya
-Mass extinction (elimination of all individuals in a species) 250 mya: Permian extinction
-Survivors spread and diversified
-Colonized newly open habitats
-Mass extinction at end of -Cretaceous period, 65 mya: extinction of between 50% and 90% of all species that occurs relatively rapidly
-Dinosaurs died out
-Pattern of extinctions followed by adaptive radiation is seen in the fossil record.
periodic bursts of species change as a result of sudden environmental change
study of how organisms are distributed in geographical space
-movement of Earth's upper mantle & crust
-Influences the geographical distribution of landmasses & organisms.
Are creature that look alike always closely related?
Common ancestry is not the only reason that two species might appear similar.
-Organisms that are not closely related evolve similar adaptations as a result of independent episodes of natural selection.
-For example, cold water fish.
Systematically identifying, naming and classifying organisms on basis of shared traits. Categories are increasingly exclusive down to only one member.
the evolutionary history of a group of organisms
-a branching diagram of relationships showing common ancestry
-Establish relationships between living organism (branches) on the basis of the ancestors they share. The more recently two groups share a common ancestor, the more closely they are related.
How many branches does the tree of life have?
Each living species sits on its own branch in a phylogenetic tree so a complete tree of life has as many branches as there are species in the world.
the highest category in modern classification
-much smaller than eukaryotic cells and do not have the same internal organization
-Unicellular and microscopic
-Lack internal membrane-bound organelles
-DNA is not contained within a nucleus
-Endlessly adaptive; can thrive just about anywhere
Prokaryotic domains: Bactria and Archaea
-have prokaryotic cells but each has a distinct evolutionary history
-archaea being genetically closer to Eukarya than to Bacteria
-the genetic differences between Bacteria and Archaea translate into a variety of structural and functional adaptations
-Most possess a cell wall
-Tremendous genetic diversity
-Differences in nutrition, metabolism, structure and lifestyle
make their own food from material in nonliving environment
rely on other organisms as a food source
-In oceans, freshwater, exposed rocks & soil
-Oldest photosynthetic organisms
-Some perform nitrogen fixation = conversion of atmospheric nitrogen into a form that plants can use for growth
-using microbes to clean up oil spills
-Cause disease by producing toxins that harm their hosts
-For example, strains of Escherichia coli secrete a toxin that causes bloody diarrhea, kidney failure, and sometimes death in its host
Bacteria structure (cocci, bacilli, spirochetes, flagella, pili, and capsule)
-Flagella: tiny whiplike structures that project from the cell and help it move
-Pili: shorter, hair-like appendages that enable bacteria to adhere to a surface
-Capsule: sticky coating surrounding cells help adhere to surfaces and protects cells
-Similar to bacteria
-Lack a nucleus
*hyperthermophiles-rely on sulfur instead of oxygen.
*methanogens-consume carbon dioxide and hydrogen and produce methane as a by-product in a process called methanogenesis. Because this gaseous meal is completely inorganic, these Archaea are considered autotrophs.
*halophiles-or "salt lovers," prefer a home saturated in salt.
-Extreme and inhospitable environment resemble ancient Earth, ~ 3.8 bya
-Prokaryotes = Most abundant living organisms
organisms with cells characterized by membrane-enclosed nucleus and organelles
-Lack roots & tissues for transporting water and nutrients
-Grow only in damp environments
-Do not produce seeds
-Have specialized tissues for transport
-first vascular plants
-vascular tissue keeps stems rigid
-seeds in fruit
-typically held in cones
-Obtain nutrients by ingesting other organisms = Heterotrophs
-Three main lineages
-Three distinct body plans
*No definite shape, asymmetrical
-Simplest living animals
-Lack defined tissues or organs (e.g. sponges)
-similar to the earliest animals to have populated the oceans
Animals Radial Symmetry
-body plan is circular
-no clear left or right sides
Animals Bilateral Symmetry
-Clear right & left halves
-Mirror images of each other
-Adaptation for seeking food, stalking prey & avoiding predators
-95% of animals
-have a bony or cartilaginous backbone
-generally with a hard shell
-slugs, snails, clams
-create passageways in the soil as they move, allow air and water to enter the soil, which is important for plants and other aerobic organisms that require water and oxygen. By eating and digesting leaf and other plant litter, earthworms also make nutrients available for other plants.
-Most abundant invertebrates
-Segmented body, jointed appendages, hard exoskeleton (protects organisms from predators, keeps it from drying out, structure and support for movement)
-Insects-arthropods with three pairs of jointed legs and a three-part body consisting of head, thorax, and abdomen.
*body covered with fur
-Unicellular or multicellular
-Obtain nutrients by secreting digestive enzymes onto organic matter and absorbing
-Body composed of threadlike structures, hyphae (singular: hypha)
digest and use organic molecules in dead organisms as sources of nutrients and energy
-a chain of many cells, capable of absorbing nutrients
-many hypha (hyphae) interweave to form mycelium, mushrooms, mold, yeast
-Eukaryotes that cannot be classified as a plant, animal or fungus
-Some are heterotrophic, algae