6
Grade 9 Science Chapter 4.notebook 1 January 08, 2014 Dec 3011:57 AM Grade 9 Science Unit 3: Reproduction Chapter 4 Dec 3012:01 PM The Function of the Nucleus The nucleus is the organelle that is responsible for heredity and for controlling the functions of the cell The control centre of the cell 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 Chromosomes are inside the nucleus (we'll get back to this later :)

Grade 9 Science - Weebly · 2018-09-09 · Grade 9 Science Chapter 4.notebook 3 January 08, 2014 Dec 3012:01 PM DNA DNA carries the instructions in the nucleus DNA is a long double‐stranded

  • Upload
    others

  • View
    4

  • Download
    0

Embed Size (px)

Citation preview

Page 1: Grade 9 Science - Weebly · 2018-09-09 · Grade 9 Science Chapter 4.notebook 3 January 08, 2014 Dec 3012:01 PM DNA DNA carries the instructions in the nucleus DNA is a long double‐stranded

Grade 9 Science ­ Chapter 4.notebook

1

January 08, 2014

Dec 30­11:57 AM

Grade 9 Science

Unit 3: ReproductionChapter 4

Dec 30­12:01 PM

The Function of the NucleusThe nucleus is the organelle that is responsible for heredity and for controlling the functions of the cell

The control centre of the cell

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

Chromosomes are inside the nucleus (we'll get back to this later :)

Page 2: Grade 9 Science - Weebly · 2018-09-09 · Grade 9 Science Chapter 4.notebook 3 January 08, 2014 Dec 3012:01 PM DNA DNA carries the instructions in the nucleus DNA is a long double‐stranded

Grade 9 Science ­ Chapter 4.notebook

2

January 08, 2014

Dec 30­12:01 PM

Responsible for Heredity

1) Trait: a particular feature that can vary in size of form from individual to individuals within a species

Traits are inherited from biological parents

2) Heredity: the process through which patterns of traits are passed on from an individual to its offspring

Dec 30­12:42 PM

Examples of TraitsTraits # of students

with trait 1# of students with trait 2

No cleft vs. cleft chin

Widow's peak vs. straight hairline

Dimples vs. no dimples

Detached vs. attached earlobes

Freckles vs. no freckles

Tongue rolling vs. not rolling

Straight thumb vs. hitch hiker's

Left thumb over right with interlacing fingers vs. right over

left

Hair on back of hand vs. none

Arm crossing ‐ left vs. right

Page 3: Grade 9 Science - Weebly · 2018-09-09 · Grade 9 Science Chapter 4.notebook 3 January 08, 2014 Dec 3012:01 PM DNA DNA carries the instructions in the nucleus DNA is a long double‐stranded

Grade 9 Science ­ Chapter 4.notebook

3

January 08, 2014

Dec 30­12:01 PM

DNADNA carries the instructions in the nucleus

DNA is a long double‐stranded molecule, it forms a helix structure (a twisted ladder)

The sides of the DNA ladder are made of sugar and phosphate

The steps are made of four nitrogen bases:1) Adenine (A)2) Guanine (G)3) Cytosine (C)4) Thymine (T)

**NOTE: A always joins with T and G always joins with C

DNA MOLECULE

Dec 30­12:22 PM

Read the article glowing genes on page 120 of your textbook!!

http://www.youtube.com/watch?v=88kMwpC7CCg

Page 4: Grade 9 Science - Weebly · 2018-09-09 · Grade 9 Science Chapter 4.notebook 3 January 08, 2014 Dec 3012:01 PM DNA DNA carries the instructions in the nucleus DNA is a long double‐stranded

Grade 9 Science ­ Chapter 4.notebook

4

January 08, 2014

Dec 30­12:01 PM

ChromosomesWhen a cell is ready to divide, each strand of loosely coiled DNA folds up further into a compact, X‐shaped structure called a chromosome

Chromosomes within the nucleus are found in pairs

Most humans have 23 pairs of chromosomes, including one pair that determines gender

Dec 30­12:01 PM

GenesGenes are found on chromosomes

Genes are small segments of DNA located at specific places on a chromosome

They store information needed to produce proteins used by body cells

Genes can vary in length from hundreds to thousands of bases, the arrangement of bases will determine the protein produced

Each chromosome contains thousands of genes

Page 5: Grade 9 Science - Weebly · 2018-09-09 · Grade 9 Science Chapter 4.notebook 3 January 08, 2014 Dec 3012:01 PM DNA DNA carries the instructions in the nucleus DNA is a long double‐stranded

Grade 9 Science ­ Chapter 4.notebook

5

January 08, 2014

Dec 30­12:01 PM

ProteinsProteins determine what body cells will become and how they will function

Specialized cells will form tissues; tissues will form organs

Specialized proteins called enzymes speed up the hundreds of chemical reactions that occur within each cell

Ex. Digestive enzymes

Some proteins act as chemical messengers called hormones Ex. Growth hormone

Bookwork: Page 121: 1‐13

Dec 30­12:01 PM

MutationsA gene mutation is a change in the specific order of the bases that make up a particular gene

A base may be:‐ Added‐ Deleted‐ Substituted for another

Open your book to page 123 and do Activity 4‐2A: Identify the Mutation

Page 6: Grade 9 Science - Weebly · 2018-09-09 · Grade 9 Science Chapter 4.notebook 3 January 08, 2014 Dec 3012:01 PM DNA DNA carries the instructions in the nucleus DNA is a long double‐stranded

Grade 9 Science ­ Chapter 4.notebook

6

January 08, 2014

Dec 30­12:01 PM

Effects of Mutations1) Positive Mutation: benefits an individual

Ex. Resistance to disease

2) Negative Mutation: harms the individual; reduces the probability that the individual will produce offspring or survive in their environment

Ex. Sickle cell anemia or cystic fibrosis

3) Neutral Mutation: does not affect the individual; things that produce variety in a species but do not give individuals advantage over one another

Ex. Hair color or eye color or blood type

Dec 30­12:01 PM

MutagensA mutagen is a substance or factor that can cause mutations in DNA

Ex. Cigarette smoke, X‐rays, pollutants

Mutagens can be caused by:1) Nature

Ex. Solar radiation or radioactive gases2) Human Activity

Ex. Chemical or nuclear radiation

Bookwork: Page 131: 1‐15