Cholesterol

LEARNING OUTCOMES

•Describe the effects of cholesterol on the body

The good, the bad, and the even better

Saturated Mono-unsaturated Poly-unsaturated

the bad The good The even better

Restoring the balanceSaturated fats (“bad fats”) increase cholesterol levels.

Mono-unsaturated fats and polyunsaturates may help reduce cholesterol and restore the balance between LDLs and HDLs.

The problem with cholesterol

• Sometimes cholesterol in the blood sticks to the inside of artery walls.

• As it builds up it forms a plaque, this restricts the flow of blood.

• Sometimes, the cholesterol can break away and block the artery completely.

Statins

• Statins are a group of chemicals which prevent all of the cholesterol being absorbed in to the blood stream

• This lowers peoples overall cholesterol – which can reduce health problems

The Big Picture

Mitosis v Meiosis

LEARNING OUTCOMES

•Compare and contrast meiosis and mitosis

•Describe adaptations of a sperm cell

The Big Picture

Egg

Haploid

23 chromosomes

Sperm

Haploid

23 chromosomes

Zygote

(fertilised egg)

Diploid

46 chromosomes

Cell in ovary

Diploid

46 chromosomes

Cell in testes

Diploid

46 chromosomes

Fertilisation

MeiosisMeiosis

Mitosis

Cell division – the differences

MITOSIS MEIOSISDiploid cells / 2n Haploid cells / n (1)

Produces identical cells Produces different cells

Involves 1 cell division 2 cell divisions

Makes 2 daughter cells Makes 4 daughter cells

Sperm adaptations• Acrosome - contains

enzymes to digest the egg cell membrane

• Tail – many mitochondria in cells to release energy.

WHY

ENZYMES

DIGESTS EGG MEMBRANE / PENETRATE / GET INSIDE THE EGG

RESPIRATION

MITOSIS – DIPLOID CELLS (46 CHROMOSOMES)MEIOSIS – HAPLOID CELLS (23 CHROMOSOMES)

MITOSIS – IDENTICAL CELLSMEIOSIS – DIFFERENT CELLS

MITOSIS – 1 CELL DIVISIONSMEIOSIS – 2 CELL DIVISIONS

MITOSIS 2 DAUGHTER CELLSMEIOSIS 4 DAUGHTER CELLS

The Big Picture

Growth spurts

LEARNING OUTCOMES

•Explain why gestation periods differ in different animals

•State that different parts of a foetus and baby grow at different rates

•Describe the main phases of human growth

Human growth

• Put the stages of human growth in the correct order, starting with the earliest:– Adulthood (maturity)– Childhood– Infancy– Old age– Adolescence (puberty)

• What stage of growth are you in?

The Big Picture

Plant cells and growth

LEARNING OUTCOMES

•Compare and contrast an animal and plant cell

•State how animals and plants grow differently

•Explain animal and plant growth in terms of cell growth

ChloroplastsCell Wall

Vacuole

Cell Membrane

Nucleus

Cytoplasm

Plant and animal cells

• Name three structures found in a plant cell but not in an animal cell

• Name three structures found in both a plant cell and an animal cell

Growth

Growth

• Plant• Most growth is due to

cells elongating (growing longer) not dividing

• Cell division only normally occurs at the tips of shoots and roots

• Many cells never lose the ability to differentiate

• Animal• Growth is due to cells

dividing• Cell division occurs all

over the body• Most animal cells lose the

ability to differentiate very early on

LEARNING OUTCOMES

•Compare and contrast an animal and plant cell

•State how animals and plants grow differently

•Explain animal and plant growth in terms of cell growth