2Chapter 4The Nucleus Controls the Functions of Life
3The Nucleus Controls the Functions of Life Think of how the workers at the Confederation Building control NL.All of the plans (DNA) for NL are kept there.
4The nucleus controls the life of a cell Nerve cells, for example, are controlled by its nucleus.The nucleus sends out messages to the rest of the cell, allowing the cell to perform activities such as obtaining nutrients, turning these nutrients into energy, growing, reproducing and getting rid of waste.
54.1 The Function of the Nucleus within the Cell The nucleus controls the functions of a living cell.DNA in the nucleus carry the master set of instructions for cell function.
6TraitsThe color of your eyes, the pitch of your voice, and the size of your nose are all traits that are passed on to you by yours biological parentsA trait is a particular feature that can vary in size or form from individual to individual within a species
7Non-pathological (do not need to study) DOMINANT TRAITRECESSIVE TRAIT (Allelic to left column)Brown eyesPTC taster Widow's Peak Middigital hair Tongue roller Detached earlobe A and B blood type (codominant) Rh positive blood type Pattern baldness (dominant in males)Blue eyes (more complex, simplified here) PTC non taster Lack Widow’s peak Hairless mid digits Cannot roll tongue Attached earlobe Type O blood type Rh negative blood type Pattern baldness (recessive in females)
8Pathological (do not need to study) DOMINANT TRAITSRECESSIVE TRAITS (Not alleles of left column)Achondroplasia Brachydactyly Congenital stationary night blindness Ehler-Danlos syndrome Fascio-scapulo-humeral muscular dystrophy Huntington disease Hypercholesterolemia Marfan Syndrome Nail-patella syndrome Neurofibromatosis PolydactylyAlbinism Alkaptonuria Atasia telangiectasia Color blindness Cystic fibrosis Duchenne muscular dystrophy Galactosemia Hemophilia Lesch-Nyhan syndrome Phenylketonuria Sickle-cell anemia Tay-Sachs disease
9HeredityIs the process through which patterns of traits are passed on from an individual to its offspring
10The Nucleus is Responsible for Heredity Cell have many organelles (cell membrane, cytoplasm, mitochondria...)The nucleus is the organelle responsible for heredity and controlling function of the cell.
11Understanding Check Give an example of a trait? What is heredity? Where is hereditary information stores?
12The Nucleus: Control Centre of the Cell Every cell in your body has a function.How do cells become retina cells vs. bone cells?The nucleus contains the master set of instructions that determines what each cell will become, how it will function, when it will grow and divide, and when it will die.
14CellsEvery cell contains in your body contains all the same information. So the cells in your heart contain the DNA for your whole body. But the cells in your heart just activate and reproduce the cell in your heart. Think of a carpenter who has the blueprints for a house but when he is in the living room he just uses those instruction to work on that room.
15The nucleus contains the master instructions that determine what each cell becomeshow it will functionwhen it will grow and divideand when it will die.
16DNA carries the master set of instructions for cell function Instruction in the nucleus are carried in long, two stranded molecules called DNA.It looks like a twisted ladder.The two strands, or sides, of the DNA ladder wrap around each other in a spiral shape that scientists call a double helix (Greek for “to wrap”)
17DNA continued... The sides of the DNA are made of sugar and phosphate The steps are made of four nitrogen bases, which are represented by the letters A (adenine), G (guanine), C (cytosine), and T (thymine)
19Arrangement of bases in DNA directs all cell activities Everything that occurs in a cell is the result of how the bases on the DNA molecule are arrangedThe arrangement is know as the DNA messageDNA bases always join in specific waysA and TG and C
20Arrangement of bases in DNA directs all cell activities continued..... The order and number of bases can vary greatly within a DNA molecule.In humans, a single DNA molecule can be several million base pairs in length.
21How is DNA stored?Most of the time it is stored in the nucleus in a loosely coiled formWhen a cell is growing, the DNA is uncoiled and aids in the making of proteinsProtein is essential material needed for the cell to carry out the activities necessary for its survival.
22How is DNA stored? Continued ... When a cell is ready to divide, each strand of loosely coiled DNA folds up further into a very compact, X-shaped structure call a chromosome
24Every organism has a characteristic number of chromosomes Chromosomes within the nucleus are found in pairsMost humans have 46 chromosomes in 23 pairs1 pair helps determine genderIn males the 23rd pair of chromosomes is XYIn females it is XX
26Comparison of Chromosomes Number in Various Organisms Human have 46 chromsomes
27Comparison of Chromosomes Number in Various Organisms Cows have 60 chromosomes
28Comparison of Chromosomes Number in Various Organisms Chickens have 78 chromosomes
29Comparison of Chromosomes Number in Various Organisms Corn has 20 chromosomes
30Comparison of Chromosomes Number in Various Organisms Butterflies had 80 chromosomes
31Comparison of Chromosomes Number in Various Organisms Bats have 44 chromosomes
32Genes – most know for their function Segments of DNA located at a specific place on a chromosome; each contains information to produce proteinsWhat gene scaredAngelina Jolie?
33Genes are Found in Chromosomes Genes are small segments of DNA located at specific places o a chromosome.Genes store the information needed to produce 90,000 to 100,000 different proteins used in the cells of your body
34Chromosome contains the coded information for thousands of traits. Chromosomes aremade up of genes.
35Chromosomes are a train and genes are the cars that make up a long train.
36Proteins determine what body cells become and how they function Each of your body cells has the same amount of genetic information stores within its 46 chromosomes.However, only specific genes are “read “in each cell to produce specific proteins.By making specific proteins , a cell becomes specialized to carry out a particular function.
37Special cells come together to form tissue (such as your retinas).
38Tissue comes together to form organs Proteins needed to make your muscles work are made on in your muscle.Proteins needed to help you read my notes are made only in your eyes.
39Enzymes and HormonesSpecialized proteins called enzymes speed up hundreds of chemical reaction in cell.Digestive enzymes break down food into nutrients molecules that provide energy for cellSome proteins act as chemical messengers called hormones. Growth hormones function to prepare a cell of division by making sure the ell has enough nutrients to divide.
40All the information is stored in long molecules called strands of DNA All the information is stored in long molecules called strands of DNA. When one cell breaks into two, it first copies the DNA so that each new cell gets a full copy.On each strand of DNA are hundreds of Genes, each gene controls a particular aspect of you. Like telling if you have blue eyes or brown for example.
42During sexual reproduction a sperm and an egg fuse to make a new individual. Half of the DNA comes from each of the two cells to form one. So half of your DNA came from your father and half from your mother.
434.2 MutationsThis is a change in the sequence of DNA. If can cause changes in the individual and can be passed down to the next generation.
44Mutation can be one of three types 1) Silent: Meaning that it did not have an effect on the product of the gene.2) Negative: Meaning that there was an effect and it somehow made things worse than before the mutation.3) Positive: Meaning that there was an effect but it made things better than they were before.
45Positive MutationA few individuals have been found to be resistant to the HIV virus and therefore, to AIDS
46Positive Mutation cont... Some plants have developed resistance to bacterial and fungal infections.Positive mutations create proteins that are beneficial to the plant and protect them from disease-causing invaders.
47Negative Mutation – Sickle Cell Anemia Negative mutations reduce the probability that organisms will produce offspring or survive in their environment.Substitution of base A for base T can cause hemoglobin to take on a different shapeAbnormal shaped molecules cannot carry oxygen efficiently.
48Negative Mutation – Sickle Cell Anemia cont... Abnormal shaped molecules block blood flow, causing pain and often organ damage since blood carrying nutrients cannon reach organs such as the lungs, liver and kidneys.
49Negative Mutation – Cystic Fibrosis It is another genetic disease caused by mutationIt can be caused by more than 1300 different mutations in one geneMucus builds up because the protein that normally functions to transport chloride ions into and out of the cell is not made correctly.
50Negative Mutation – Cystic Fibrosis This causes respiratory problems
51Neutral MutationA substitution of one base for another base DNA sequence may not change an organism (misspelled word does not change a sentence)The same protein will be made and may still function normallyThe change does not effect survival rate of organism
52Let us look at a comparison for DNA SequenceIngredientGeneRecipeChromosomeRecipe BookNucleusBook ShelfCellLibrary