Presentation on theme: "Unit 3: Growth and Heredity"— Presentation transcript:
1Unit 3: Growth and Heredity Cells can grow only so big before they need to divide
2Mitosis (Cell Division) nucleus divides into two nucleinumber of chromosomes remain the same.
3Mitosis Prophase (1st Phase) Chromosomes become visible Continuous process4 Stages of MitosisProphase (1st Phase)Chromosomes become visibleCell part that contains genes that express traits that is located in the nucleusMade up of thread-like material-chromatinControl cell processes and determine traits of the entire organismsNuclear envelope dissolvesSpindle forms (centrioles)Attach to chromosomes
5Mitosis Metaphase (2nd Phase) Chromosomes line up along the equator (middle of the cell)
6Mitosis Anaphase (3rd Phase) Centromeres divide ( connects the chromatids together)Chromatids are single strands of chromosomesChromatids move toward opposite poles (spindle fibers are getting shorter)
7Mitosis Telophase (4th Phase) Nuclear envelope forms at each pole Chromosomes unwindCytokinesis begins
8Mitosis and Cytokinesis Cytokinesis-as mitosis ends this process beginsCytoplasm dividesForms two new cellsEnd result of mitosis and cytokensis: 2 diploid (2n) identical cells
9Cytokinesis: Plants and Animals Animals - cell pinches inwardPlants - a new cell wall forms between the two new cells
10The cell cycle is carefully controlled Checkpoints (traffic lights)-check for errors, correct mistakes and stop the process.
11MitosisPurpose:Replace old and worn out cells lost by wear and tear. Ex. Skin sheddingRequired to sustain lifeImmature human=growthMitosisType of Cells that divide in this processBody cells (hair, skin etc.)
12MeiosisProcess by which gametes (reproductive cell) are formed (egg and sperm cells)Sperm Cell-male reproductive cellEgg Cell- female reproductive cellGametes contain half the number of chromosomes as body cells.Because offspring will get a copy of genes from each parent.Example: Female Gamete=23 chromosomes and Male Gamete=23-Zygote (fertilized egg has 46 chromosome)
13MeiosisForm of cellular division that halves the number of chromosomesTwo cell divisions-meiosis I and IITotal of eight phasesStarts with homologous chromosomesare similar in shape and contentEnd result: 4 haploid (n) genetically different cells.
14ChromosomesMade up of thread like material (DNA) called chromatin (prophase)Located in the nucleus (control center of the cell)Control cell processes and determine the traits of the entire organisms (hair color, height , eye color etc.)Comprised of two sister chromatids (single strand of chromosomes) that are identical in contentDuring cell division, each chromosome makes an exact copy of itself.Genes ( part of chromosome that controls inherited traits-eye color, height, etc.) are located on different parts of chromosome
17Purpose of MeiosisPrimary purpose is to increase genetic variations (differences)
18Meiosis Provides Variations (Differences) 3 mechanisms contribute to genetic variations (Differences)Independent assortment, crossing-over and random fertilization
19Independent Assortment Random distribution of homologous chromosomes during meiosis (genetic shuffling)Siblings look similar but different because they have some genes in common.
20Random fertilization Only one sperm will enter the egg Only one sperm will fertilize an eggEach sperm carries a different combination of genesAllows for unlimited genetic combinationsOnly one sperm will enter the egg
21Crossing Over Occurs in Prophase I Portion of one homologous chromosome is exchanged with a portion of another homologous chromosome
22Importance of Genetic Variation Increases the speed of evolution (change)Allow favorable traits (thick fur) to pass from one generation to the next that increase chances of survival
23Asexual Reproduction (Mitosis) Asexual reproduction-a single parent passes copies of all of its genes to each of its offspringClone-organism that is genetically identical to its parent
24Sexual Reproduction (Meiosis) Sexual reproduction-two parents each form haploid reproductive cells (sperm and egg), which join to form offspring.Have traits from both parentsNot exactly like parents
25Advantages of and Disadvantages of each type of reproduction Asexual reproduction:Disadvantage: lack of diversity that threatens the ability of the organisms to adapt in a changing environmentAdvantage: allows organisms to produce many offspring in a short period of time without using energy
26Advantages of and Disadvantages of each type of reproduction Sexual Reproduction:Advantage: enables organism to adapt to changing environmentDisadvantage: requires lots of energy and produce only a few organisms at a time.
28Venn Diagram: Asexual vs. Sexual Reproduction Insert the following terms into the right part of the circle.1. one parent2. two parents3. clone4. different from parent5. requires more energy6. difficulties adapting to a changing environmentList two similarities in the middleExplain why genetic differences are important?
29HeredityMany of your traits (characteristics of an organism)-eye color, hair color-resemble your parents.Inherited traits: traits that are passed from parents to their offspring.Eye ColorHeredity-passing of traits from parents to offspringStudy of heredity began with Gregor MendelGenetics-focuses on heredity
31Mendel’s Studies Based his hypotheses on pea plants Concluded the following:1. An individual inherits two copies of a gene-one from each parent
32Mendel’s Theories 2. There are alternative versions of genes Ex. Flower Color: purple and white
33Mendel’s Theories 3. Some traits are expressed and others are hidden. Dominant: gene whose trait always shows itselfRecessive: gene of a trait that is hidden when the dominant gene is present.
34Mendel’s findings in modern terms Homozygous-two alleles are the sameEx. AA or aaHeterozygous-two alleles are differentEx. AaHeterozygous only dominant trait is expressedEx. F=freckles f=no freckles Ff=
35Mendel’s findings in modern terms Genotype-set of alleles (letters) ex. FfPhenotype is the physical appearance ex. Freckles
36Mendel’s Ideas Give Rise to the Laws of Heredity Law of segregation-Alleles for a trait separate when gametes are formed.These allele pairs are then randomly united at fertilization (uniting of the egg and sperm to form zygote (fertilized egg)
38Studying HeredityPunnett Squares-chart that shows possible gene combinationsOrganisms have at least two genes for most traits.An uppercase letter represents a dominant traitA lowercase letter represents a recessive trait
39Mini Lab Follow procedures found on p. 281 Answer analysis questions after completing the punnett square problems.
40Left Side Divide page into six and define the following terms: Homozygous, heterozygous, phenotype, genotype, dominant and recessiveFor each term complete the following:Definition, drawing , and sentence using the term correctly (put sentence in a box).
41Acquired Traits vs. Inherited Traits Acquired Traits are traits that you learn because of the environment that you live in.Example: favorite color or favorite foodInherited Traits are traits that are passed from generation to generation by genes inherited from your parents.Ex. Eye color, hair color.
42Non-Mendelian Patterns of Inheritance All human traits are determined by 23 pair (46 chromosomes) of chromosomes.23rd pair are not alikeMales=XYFemales=XXThe X and Y chromosome determine gender (male or female)All eggs contain X chromosomesSperm cell can contain either a X or Y chromosomeGender is inherited (determined) from the father
43Sex-Linked TraitSex-Linked Traits-traits that are inherited along with gender.X chromosomes carries many genesY chromosome carries few genesMost genes for sex-linked traits are found on the X chromosome.Sex-linked disorders are found more often in men than women.Most genes for sex-linked disorder is recessiveMen only have one X chromosomeIf they inherit trait they will have the disorder.
44Patterns of HeredityPolygenic trait-traits that are influenced by several genes.Ex. Hair color, skin color, weight, height, and eye color
45Intermediate traitsIncomplete dominance- pattern of inheritance in which alleles from both parents are blended.Ex. red flower is crossed with white flower-offspring pink flowers
47Traits with two formsCo-dominance- pattern of inheritance in which both alleles of a gene is expressed.Ex: Both red and white will be displayed on the flower
48Jumping Genes (Genetic Variation) Genes that move around or jump around and relocate.Create new genetic combinationsOnly take place on certain genes (wouldn’t want your heart genes jumping around and relocating)
49DNA Blueprint of the organism Controls everything about the way that you look( color of your eyes to width of your feet)Transfers characteristics from one generation to the next
50The structure of DNA Watson and Crick determined the structure of DNA Three dimensional modelDNADouble helix-two strands twisted around each other like a winding staircaseEach strand is made of linked nucleotidesMade up of three parts: phosphate group, a five-carbon sugar, and a nitrogen-containing base.Five carbon sugar: deoxyribose
51Structure of DNA.4 Nitrogen bases- adenine(A), guanine(G), thymine(T), and cytosine(C)Double helix is held together by weak hydrogen bonds
52Base Pair RuleRule that explains how nitrogen bases pair up on the DNA moleculeA (adenine) pairs with (T) ThymineGuanine (G) pairs with Cytosine (C)Build a DNA Molecule
53The Replication of DNA Takes place in interphase Process of making a copy of DNADNA molecule unzips between nitrogen basesNew nitrogen bases pair up and attach to each half of the ladder.Two new DNA strands that are exact copies of the original DNA molecule
54Checking for errors DNA polymerase: proofread role Corrects mistakes in nucleotide bases
55Left Side AssignmentWrite an analogy story that relates to each step of DNA replication. Each paragraph should relate to each step of replication.Step 1: something unzipsStep 2: something is addedStep 3: a copy is madeThis should be written in color.
56Expression of TraitsTraits such as eye color are determined by proteinsSpecific instructions are found on DNAProteins are not built directly from DNAToo large to fit through the nuclear pores
57RNA Is a special molecule that is used to make proteins Ribonucleic Acid (RNA)Different from DNA in many waysSingle strandedHas a new nitrogen base: uracilDoes not have thymineDifferent sugar: ribose
58From Genes to ProteinsGene ExpressionStep one: instruction are transferred from DNA to RNA molecule in process called transcriptionStep Two: Translation (takes place in cytoplasm)-process in which cell uses two different RNA molecules to read the instructions on the RNA and put together the amino acids that make up proteinstRNA: transfers the amino acids to the ribosome's site of protein synthesis
59The Genetic Code is Written in Three-Nucleotide “Words” Codons-series of three-nucleotide sequences on the mRNA (messenger RNA) that translate into the amino acids that make proteins.EX. AUC codes for the amino acid_______
60From Genes to ProteinsSIMPLY PUT: DNA makes RNA makes Proteins make traits( such as eye color, skin color and hair color)
61Mutations Any change in an organisms genetic material. Can be harmful if it decreases the organism’s ability to function properly.Abnormalities can be detected in a karyotype.A photo of the chromosomes
63Two Types of MutationsGene Mutations: result from changes in a single geneChromosomal Mutations: involve changes in an entire chromosome.Deletion- a piece of a chromosome breaks offDuplication-two copies of a certain set of genes
64Point Mutations Change in one or just a few nucleotides Sickle Cell Anemia is caused by this type of mutation.
65Mutations Cont.Mutations in gametes (egg and sperm) can be passed on from generation to generation.Color blindnessMutations in body cells (somatic cells) affect only one individual.Lung cancer
66Down Syndrome (Mutation) Caused by extra copy of 21st chromosome (non-disjunction-when one or more chromosomes fail to separate)Individuals with this conditionShort stature, a round face , and varying degrees of mental retardation.
68Mutations External influences can create mutations. Mutations can be caused by exposure to specific chemicals or radiationExample: Lung CancerChemicals found in the cigarettes cause mutations in lung cells.Example: Skin CancerUltraviolet Rays cause mutations in skin cells.
71Detecting Genetic Disorders Most can not be cured.Persons’ with family history may wish to undergo genetic counseling.Genetic Counseling- medical guidance that informs people about genetic problems that could affect them or their offspring.
72Genetic Engineering Methods used to produce new forms of DNA. Involves building NEW DNA by taking genes from one species and inserting them into a completely different species.Examples of Genetically Engineered Items1. Tomatoes with elephant genes (make the tomatoes grow larger)
73Benefits of Genetic Engineering Medicines to treat disease such as diabetes.Identify individuals and establish relationships -DNA fingerprinting
74Benefits of Genetic Engineering Add favorable characteristics to a plantResistant to pest or pesticidesTolerate harsh environmental conditions such as drought
78DisadvantagesExperimenting with Bacteria can cause new diseases with no cure.Federal Government regulates experiments because of danger.
79QuestionsCreate three questions and a two sentence summary for your notes.Make sure you write your questions next to the answer in the notes.Make one of your questions a How?
80Snappy ProductsYou are a design team for a small biotechnology company.Your Job is a follows:1. Brainstorm a list a ways that you can improve popcorn.Ex. Popcorn that pops faster2. Think of something else that has the desired trait that you want to see in your popcorn.3. Combine the solution that you thought of in #2 with popcorn, make the “the popcorn” that can solve the problem that you mentioned in #1.Assignment: Draw your new popcorn product, be sure to clearly show what other product that you combined with your popcorn to create something new.Create a catchy name for you productWrite a tune with words to be used to as a radio commercial. Include your price in your song.