GENETICS – DNA, CHROMOSOMES AND

GENESPEARSON CH 1 PAGE 1

COLOUR BLINDNESS

LEARNING GOALSMy Learning goal for the first part of this term is:

I can explain how characteristics are inherited and predict the probable genetic make up of following generations.• The transmission of heritable characteristics from one generation to the next

involves DNA and genes (ACSSU184) CHAPTER 1 Pearson

I can use the theory of evolution to explain the diversity of life on the planet and I can provide a range of scientific evidence supporting the theory.

• The theory of evolution by natural selection explains the diversity of living things and is supported by a range of scientific evidence (ACSSU185) CHAPTERS 2, 3 Pearson

M Movement All living things move, even plants

R Respiration Getting energy from food

S Sensitivity Detecting changes in the surroundingsG Growth All living things grow

R Reproduction Making more living things of the same typeE Excretion Getting rid of waste

N Nutrition Taking in and using food

Living things have certain life processes in common. There are seven things that they need to do to count as being alive. The phrase MRS GREN is a way to remember them:

3 DOMAINS OF LIFE

• Archaea - These microbes are Prokaryotes, meaning that they have no cell nucleus or any other membrane-bound organelles in their cells, but are different to Bacteria

• Bacteria – are also Prokaryotes were among the first life forms to appear on Earth, and are present in most of its habitats.

• Eukaryotes - is any organism whose cells contain a nucleus and other organelles enclosed within membranes.

5 KINGDOMS OF LIFE

• Living organisms are divided into five kingdoms: Prokaryotae, Protista, Fungi, Plantae, Animalia

• Prokaryotae /Monera - Unicellular and Microscopic. Non-membrane bound (no nuclear membrane, no ER, no mitochondria). Cell wall made of murein. Examples: Bacteria or Cyanobacteria (photosynthesising bacteria).

HEREDITY

Reproduction – Fish, dinosaurs , all birds lay eggs but not peacocks. Why?

Go to the Yr 10 Genetics wiki for the science of Spiderman

Heredity is the passing of traits to offspring from its parents or ancestor. This is the process by which an off-spring cell, or organism acquires or becomes predisposed to the characteristics of its parent cell or organism. Through heredity, variations exhibited by individuals can accumulate and cause some species to evolve. The study of heredity in biology is called genetics.

THE CELL - INTRODUCTION• Cell A cell is the smallest part of a living thing that can carry out all the

processes of life - all life originates from previous life.• Cell membrane A thin, flexible barrier around a cell that

separates it from its surroundings; regulates what enters and leaves the cell, thus giving the cell control over its processes.

• Cytoplasm it contains the cell contents and the organelles and is gel-like.• Nucleus the centre of the cell that contains the genetic material

of cell and separated from the remainder of the cell by a nuclear membrane

TYPES OF LIFE (CELLS)

• Prokaryotic cell this type of cell is more primitive and does not contain a nucleus so its genetic material floats freely in the cytoplasm eg bacteria

• Eukaryotic cell composes all complex living things, it must contain a nucleus (with the genetic material of the cell segmented from the remainder of the cell by a nuclear membrane)

DNA GENES AND CHROMOSOMES

Genes and chromosomes• Our bodies are made up of millions of cells. Most cells contain a 23 pairs of

chromosomes (made of DNA strands) which is a complete set of genes. We have thousands of genes. Genes act like a set of instructions, controlling our growth and how our bodies work. They are responsible for many of our characteristics, such as our eye colour, blood type or height.

http://yr10-genetics.wikispaces.com/Ch+1+-+DNA

GENES AND CHROMOSOMES

• Chromosomes long thread-like structures composed of DNA and found only in the nucleus of the cell - 23 pairs are found in most cells of the body - the only exceptions are egg cells, sperm (23 single chromosomes) and red blood cells (nil)

• Genes sections of a chromosome that code for particular proteins that lead to specific characteristics eg blue eyes or dark hair. It usually takes multiple genes to code for any given characteristic - so this is quite complex.

DNA

• DNA deoxyribonucleic acid - the double stranded helix that forms the basis of genes and chromosomes - determines the characteristics of organisms. The genetic blue-print.

• Nucleotides the basic units of DNA - contains a phosphate group, deoxyribose sugar and one of four Nitrogen rich bases.

• Phosphate groups bind with the deoxyribose sugars to form the spine of the DNA molecule

• Deoxyribose sugar binds with one of the four Nitrogen rich bases (side-ways) and to the phosphate groups (along the double helix)

• Nitrogen rich bases adenine (A), thymine (T), guanine (G) and cytosine (C)

NUCLEOTIDE

COMPLEMENTARY BASE PAIRING

• Complementary base pairing - adenine (A) can only bond with thymine (T), and guanine (G) can only bond with cytosine (C). A-T and G-C (Always Teach Good Classes)

REPLICATION

Copy this diagram and explain this 3 step process.