Reproduction

Unit 4

The Nucleus Controls the Functions of Life

Chapter 4

Think of how the workers at the Confederation Building control NL.

All of the plans (DNA) for NL are kept there.

The Nucleus Controls the Functions of Life

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.

The nucleus controls the life of a cell

The nucleus controls the functions of a living cell.

DNA in the nucleus carry the master set of instructions for cell function.

4.1 The Function of the Nucleus within the Cell

The 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 parents

A trait is a particular feature that can vary in size or form from individual to individual within a species

Traits

DOMINANT TRAIT RECESSIVE TRAIT (Allelic to left column)

Brown eyes

PTC 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)

Non-pathological (do not need to study)

DOMINANT TRAITS RECESSIVE 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 Polydactyly

Albinism Alkaptonuria Atasia telangiectasia Color blindness Cystic fibrosis Duchenne muscular dystrophy Galactosemia Hemophilia Lesch-Nyhan syndrome Phenylketonuria Sickle-cell anemia Tay-Sachs disease

Pathological (do not need to study)

Is the process through which patterns of traits are passed on from an individual to its offspring

Heredity

Cell have many organelles (cell membrane, cytoplasm, mitochondria...)

The nucleus is the organelle responsible for heredity and controlling function of the cell.

The Nucleus is Responsible for Heredity

Give an example of a trait?

What is heredity?

Where is hereditary information stores?

Understanding Check

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.

The Nucleus: Control Centre of the Cell

Cell Dying

Every 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.

Cells

what each cell becomes how it will function when it will grow and divide and when it will die.

The nucleus contains the master instructions that determine

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”)

DNA carries the master set of instructions for cell function

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)

DNA continued...

Everything that occurs in a cell is the result of how the bases on the DNA molecule are arranged

The arrangement is know as the DNA message

DNA bases always join in specific ways A and T G and C

Arrangement of bases in DNA directs all cell activities

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.

Arrangement of bases in DNA directs all cell activities continued.....

Most of the time it is stored in the nucleus in a loosely coiled form

When a cell is growing, the DNA is uncoiled and aids in the making of proteins

Protein is essential material needed for the cell to carry out the activities necessary for its survival.

How is DNA stored?

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

How is DNA stored? Continued ...

Chromosomes within the nucleus are found in pairs

Most humans have 46 chromosomes in 23 pairs

1 pair helps determine gender In males the 23rd pair of chromosomes is XY In females it is XX

Every organism has a characteristic number of chromosomes

Human have 46 chromsomes

Comparison of Chromosomes Number in Various Organisms

Cows have 60 chromosomes

Comparison of Chromosomes Number in Various Organisms

Chickens have 78 chromosomes

Comparison of Chromosomes Number in Various Organisms

Corn has 20 chromosomes

Comparison of Chromosomes Number in Various Organisms

Butterflies had 80 chromosomes

Comparison of Chromosomes Number in Various Organisms

Bats have 44 chromosomes

Comparison of Chromosomes Number in Various Organisms

Segments of DNA located at a specific place on a chromosome; each contains information to produce proteins

What gene scared Angelina Jolie?

Genes – most know for their function

Genes 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

Chromosome contains the coded information for thousands of traits.

Chromosomes are made up of genes.

Chromosomes are a train and genes are the cars that make up a long train.

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.

Proteins determine what body cells become and how they function

Special cells come together to form tissue (such as your retinas).

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.

Tissue comes together to form organs

Specialized proteins called enzymes speed up hundreds of chemical reaction in cell.

Digestive enzymes break down food into nutrients molecules that provide energy for cell

Some 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.

Enzymes and Hormones

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.

During 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.

This is a change in the sequence of DNA. If can cause changes in the individual and can be passed down to the next generation.

4.2 Mutations

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.

Mutation can be one of three types

A few individuals have been found to be resistant to the HIV virus and therefore, to AIDS

Positive Mutation

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.

Positive Mutation cont...

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 shape

Abnormal shaped molecules cannot carry oxygen efficiently.

Negative Mutation – Sickle Cell Anemia

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.

Negative Mutation – Sickle Cell Anemia cont...

It is another genetic disease caused by mutation

It can be caused by more than 1300 different mutations in one gene

Mucus builds up because the protein that normally functions to transport chloride ions into and out of the cell is not made correctly.

Negative Mutation – Cystic Fibrosis

This causes respiratory problems

Negative Mutation – Cystic Fibrosis

A 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 normally

The change does not effect survival rate of organism

Neutral Mutation

Sequence Ingredient

GeneRecipe

ChromosomeRecipe Book

NucleusBook Shelf

Cell Library

Let us look at a comparison for DNA