• Nucleus directs cell activities through chromosomes (long strand of DNA)

• DNA = molecule that stores genes = ‘programming’ for cell structures + activities.

• Nuclear membrane allows materials to pass into/out of nucleus

• Nucleolus = site for production + assembly of ribosomes (make proteins)

• Rough endoplasmic reticulum has ribosomes attached, transports proteins

• Smooth Endoplasmic Reticulum no ribosomes, manufactures + transports fats

• Cytoplasm contains specialized microtubules (assist movement of organelles) called centrioles.

DNAdeoxyribonucleic acid

Is your friend….

Lesson objectives

• Know what DNA is• Understand the structure of DNA• Know what the ‘base pairs’ are• Know the difference between dominant

and recessive genes

• DNA molecule = two strands of smaller molecules, called nucleotides.

• The sides of the DNA ladder are made of the sugar and phosphate molecules joined to each other.

• There are four different nitrogenous bases: adenine (A), thymine (T), cytosine (C), and guanine (G). • Pairs of these bases form each rung of the

DNA ladder. – Adenine always pairs with thymine (A-T)– cytosine always pairs with guanine (C-G)

• These are sometimes referred to as base pairs.

• Before a cell divides, each DNA molecule makes a copy of itself.

• Each DNA molecule splits in many places between the pairs of bases, like a broken zipper.

• New bases join up with the bases on each of the opened sides of the ladder to form two identical DNA molecules

Dominant or recessive?

• We all have genes in our DNA which aren’t expressed, but could be passed on to our children

• You might have a gene for red hair (which is recessive) and a gene for brown hair (which is dominant), so you would have brown hair

• The most common traits people have are the result of dominant genes.

Conduct an experiment to determine a dominant and recessive gene

1. Make a prediction (for example, I predict that the gene for straight hair is dominant and the gene for curly hair is recessive).

2. Collect Data- walk around the classroom and survey your classmates.

3. Conclusion- What are the results? Did the data support your prediction?

4. Verify your results- research genes and find out whether your results reflect reality.