Making babies Unit

Year 10

DNA Structure and Function

DNA

• If you flatten out a double helix shaped DNA molecule, you can see that the DNA is made up of bases, of which there are four different kinds in DNA. They are shown below using the letters A, T, C and G. The order in which these bases occur makes up the genetic code. DNA video

Base pairing.

• The A goes with T and the G goes with C.

DNA replication.

• How does DNA make copies of itself?

Today

• Keywords 1-10

• Review DNA.

• DNA video.

• Handout 2.

• Mitosis steps; scientific name.

Mitosis

http://www1.teachertube.com//googleSearch.php?cx=012339422634307447803%3Ah-vlw-wg9yy&cof=FORID%3A11&ie=UTF-8&q=mitosis&sa=Search

• Living things grow by cell d_________ . When a cell gets to a certain size, the c_____________ are copied. Each new cell gets an i___________ copy of the chromosomes, because the D____ in the chromosomes provides the instructions for everything cells do. Once the cells are ready to divide, the chromosomes c______ up and become visible. The chromosomes line up across the middle of the cell and one copy of each chromosome is pulled to each side of the cell by i________ strands. Once the chromosomes have pulled apart, a new cell w_____ forms, creating two cells, which can continue to grow.

Cell division

Mitosis

• For growth & repair.• Makes 2 identical cells.

Meiosis

• For sexual reproduction.• Makes eggs and sperm

with half the normal amount of DNA.

Today

• KW 11-20

• Animal cells

• Animal cell models

Animal Cell Structure

Organelles

• Cell membrane- holds the organelles within the cell.

• Cytoplasm- jelly-like substances containing water, sugar & salts.

• Nucleus- holds the DNA.

• E.R.- makes chemicals.

• Mitochondria- powerhouse of the cell, turns glucose into ATP.

• Ribosomes- make proteins.

• Golgi bodies- transports chemicals around the cell and body.

• Centrioles- make spindle fibres for mitosis

Drawing Cheek Epithelial Cells

Animal cells- specialized.

• You are to create a specialized animal cell to display on the wall.

• You are to label the important organelles for your cell and give a brief description of the cells function.

Animal Cell Types

Info-graphic.Neuron (nerve cell)

This cell carries electrical signals from the brain to all parts of the body.

It has more mitochondria than other cells, as it uses lots of energy sending the signals.

Neurons are found in the brain, spinal cord and the whole central nervous system.

Meiosis.

• Cell division for sexual reproduction. • Its like double mitosis, but with crossing

over! Meiosis square dance

Early Prophase.

Late prophase.

Metaphase.

Anaphase.

Telophase.

Cytokinesis.

Meiosis

Diploid – 2 copies of each chromosome (2n)

Haploid – 1 copy of each chromosome (n)

Mitosis

Growth & repair Gamete production for sexual reproduction.

Meiosis

Mitosis Meiosis

Life Cycles

http://www.bootslearningstore.com/ks4/repro.html

Variation in Humans

• Continuous variation occurs where there is a range of values for a characteristic.Examples: height weight IQ hand span shoe size

• Discrete (either/or) variation occurs where a characteristic, or trait is either present or absent.Examples: left/right handed attached/hanging earlobe long second toe double-jointed/not can/cannot roll tongue hitch-hikers’ thumb

widow’s peak

Either/or variation

Trait Yes No

Widows peak

Left handed

Blue eyes

Hitch hikers thumb

Tounge roller

Continuous variation.

Person Height Hand span

Oliver 167cm 21cm

Josh 173cm 24.5cm

Holly 170cm 19cm

Tai 169cm 20cm

Ellen 177cm 20cm

Leaha 167cm 19cm

Sarah 169cm 21cm

Tori 163cm 18.6cm

Mrs L 174cm 18cm

Our class

Height range Number

160-164 cm 1

165-169 cm 4

170-174 cm 3

175-179 cm 1

The Bell curve

Variation

Height (cm) Number

136-139

140-143

144-147

148-151

154-157

158-161

162-165

166-169

170-173

174-177

178-181

Human reproduction

Female hormone cycle.

Male reproductive system.

Pregnancy

• When a sperm and egg fuse, a pregnancy may result.

• Human pregnancy lasts around 40 weeks.

• The growing baby relies on the mother for everything it requires to grow.

• The placenta and umbilical cord connect the mother and child.

Overview of the three stages of labour

The first stage of labour

The first stage of labour is the dilatation of the cervix. The cervix is the neck of the womb (or uterus) which opens into the vagina. This is closed throughout and at the end of pregnancy, but needs to open to allow the baby to pass through into the vagina in order to be born.

The first stage of labour begins when the woman experiences regular, rhythmic contractions and it is complete when the cervix has fully opened to around 10 cm dilated

.

The second stage of labour

The second stage of labour begins when the cervix is fully dilated and is complete when the baby has been born. During this time the woman will add her effort of pushing and bearing down to the expulsive contractions to birth the baby.

The third stage of labour

The third stage of labour begins directly after the birth of the baby and involves the separation and the delivery of the placenta and membranes (the after birth). The third stage of labour is complete when the mother has successfully passed the placenta and membranes. 

So what happens when people can’t get pregnant?

IVF; In vitro fertilisation

• When both egg and sperm are ‘normal’.

• The female egg and male sperm are combined outside the body and the zygote placed back into the uterus for maturation.

Stages of IVF

1. Ovulation Induction

2. Egg Retrieval

3. Collecting and preparing the sperm

4. Insemination of eggs and embryos culture

5. Transferring embryos to the uterus

Intracytoplasmic sperm injection (ICSI).

When the egg is normal but the sperm are not.

Cloning.

• Creating an exact copy of an organism.

Brain pop- Dolly

Gregor Mendel

Words!

• Genotype- the 2 letters that represent the gene’s.

• Phenotype- what the trait looks like.• Heterozygous- 2 different genes• Homozygous- 2 of the same genes• Dominant- Only 1 is required for the trait to

show• Recessive- 2 copies required for the trait to

show.

Punnet squares

Punnet squares

Punnet square sheet.

• In humans, brown eyes (B) are dominant over blue (b). A brown-eyed man marries a blue-eyed woman and they have three children, two of whom are brown-eyed and one of whom is blue-eyed. Draw the Punnett square that illustrates this marriage. What is the man’s genotype? What are the genotypes of the children?

Punnet square sheet.• In dogs, there is a hereditary

deafness caused by a recessive gene, “d.” A kennel owner has a male dog that she wants to use for breeding purposes if possible. The dog can hear, so the owner knows his genotype is either DD or Dd. If the dog’s genotype is Dd, the owner does not wish to use him for breeding so that the deafness gene will not be passed on. This can be tested by breeding the dog to a deaf female (dd). Draw the Punnett squares to illustrate these two possible crosses. In each case, what percentage/how many of the offspring would be expected to be hearing? deaf? How could you tell the genotype of this male dog? Also, using Punnett square(s), show how two hearing dogs could produce deaf offspring.

Punnet square sheet.

• In pea plants, round peas are dominant over wrinkled peas.Use a Punnett square to predict the phenotypic and genotypic outcome (offspring) of a cross between two plants heterozygous for round peas.

Q1. What is the structure and function of DNA?

Q2. Draw a label a general human body cell, a sperm cell and an egg

cell.

Q3. What are the key differences between mitosis and meiosis?

Q4. Define these words;

• Genotype;

• Phenotype;

• Homozygous;

• Heterozygous;

• True breeding;

• Gene;

• Allele;

• Q5. If brown hair (B) is dominant over blonde hair (b); complete a Punnett square for a blonde father and a heterozygote brown mother.

• Phenotypes: ____________________• Genotypes: _____________________