3.20 Pedigree Diagrams (a)

3.20 Understand how to interpret Pedigree diagrams

• The shaded in diagrams usually represent an inherited condition a male or female has recieved
• Circles and squares represent phenotypes
• Vertical lines represent the bond from parent to child
• Horizontal lines represent partners bond
• An open circle or open square is referred to as"normal" whereas a shaded circle or square is referred to as "affected"

What does each line represent?

3.19 b F1 x F1 Cross

3.19 a P1 x P1 Cross

3.18 b Genotypes

3.18a Phenotypes

3.12 - Amniotic fluid

In the uterus space there is the amniotic fluid

functions: 

- can protect the developing embryo - comes from the fluid  (largely water) not being able to be compressed. 

- When you try to squeeze the fluid it absorbs the pressure. 

- This means any blows or force applied to the uterus wall - the amniotic fluid will absorb this pressure and will prevent damage to the unborn child. 

example of absorbing the pressure: 

in a swimming pool when you try to kick it with your leg - leg doesn't move very quickly, hard to generate great force. - example of how the fluid absorbs the force. 

3.11 - Placenta

when the child is in the uterus - water filled environment (amniotic fluids) - child cannot digest or breath or excrete

- baby obtains food - blood vessels lead from the embryo down the umbilical cord and then spread out to form placenta. 

- placenta biologically grows out of the developing embryo. not out of the mother. 

- blood vessels inside the placenta are the child's (veins and arteries) 

- placenta grows into the lining of the uterus (wall) 

- mother continues to eat and so in the blood vessel we have things like glucose, amino acids and fats. these travel through blood stream and into the wall of the uterus. they then cross into the childs blood at the placenta. 

- to make this efficient the placenta has a large surface area and the barrier between the mother and childs blood is very thin. 

- child produces CO2 and Urea which then goes back into the mothers blood.