3.19b F1 x F1 Cross

3.19a P1 x P1 Cross

3.18b Genotypes

3.18a Phenotypes

3.10 Menstrual Cycle

understand the roles of oestrogen and progesterone in the menstrual cycle.
-oestrogen and progesterone are examples of hormones.
-hormones are produced in a structure called and endocrine gland.
-hormone will travel through the blood from the endocrine gland to target tissue.
-at the target tissue the hormone will have an effect. (may have multiple effects)
-ovary is the endocrine gland for oestrogen, it produces oestrogen which flows in the bloodstream to the lining of the uterus where it has effect no.1 which is the thickening of the endometrium. effect no.2 is that it flows to the bloodstream to the brain and it releases a second hormone known as luteinising hormone (LH) the production of luteinising hormone reaches its peak at around day 13- causes the ovary to release an egg into the oviducts where it is possible for fertilisation.

-in ovary- during the first half of the menstrual cycle the follicle becomes larger and larger- inside follicle is an egg. the cells around the follicle is producing oestrogen.
-the follicle reaches it largest point at around day 13 when the luteinising hormone causes the wall of the outside to rupture and the egg is released. - called ovulation.
-once process is complete the empty follicle changes function and colour (to yellow) gives us the name corpus lutetium (known as the yellow body) this yellow body is known to produce progesterone.
-ovary and the corpus lutetium in particular is the endocrine gland for progesterone.

-progesterone travels through the blood stream to the lining of the uterus to give effect no.3 to maintain the lining of the uterus- prevents the lining of the uterus from breaking down.
-in this condition it is possible that a fertilized egg could implant to the wall of the uterus and develop into a pregnancy.
-but if there is no implantation of an fertilized egg the corpus lutetium breaks down and progesterone levels fall.

-the fall in progesterone levels lead to effect no. 4
-which is the breakdown in the lining of the uterus- menstrual period/menstrual bleeding.
-marks end of one menstrual cycle and a start of a new menstrual cycle.
-when the lining has broken down completely the cycle and the change in hormones begins one more.

2.4 Plant and Animal Cells

describe the differences between animal and plant cells.

ANIMAL
-has a nucleus, cytoplasm, and has a cell membrane like a plant cell.
-but it stores glycogen (a type of carbohydrate) as the molecule and it has an irregular shape.

PLANT
-has a nucleus, cytoplasm, and has a cell membrane like an animal cell
-but it has a cell wall, chloroplasts, large central vacuole and is in a regular shape.
-plant cell stores the molecule starch (a type of carbohydrate).

life cycle

mitosis

3.12 Amniotic fluid

understand how the developing embryo is protected by amniotic fluid
-in the uterus space there is a fluid called the amniotic fluid.
-the function is that it can protect the embryo- the fluid (largely water) cannot be compressed.
-when you try to squeeze the fluid it absorbs the pressure.
-any blows or force applied to the uterus wall, the amniotic fluid will absorb this pressure and prevent damage to the unborn child.
-another function is floating- this is because the bones cannot support the child yet as they are not calcified (hard) at that time.

if you want to experience the effect of absorbing the pressure
- if you are standing in the swimming pool and you try to kick out- your leg doesn't move very quickly and it is difficult to generate great force- example of how the fluid absorbs the force.

3.11 Placenta

describe the role of the placenta in the nutrition of the developing embryo.
-on one side of the wall of the uterus there is a placenta.
-when the child is in the uterus it is in a water filled environment (amniotic fluid) the child cannot digest, breathe or excrete.
-growing out of the developing embryo there is a placental structure (umbilical cord)
-the blood vessels inside the placenta are the child's blood vessels (arteries and veins)
-the placenta grows into the wall of the uterus.
-the mother continues to eat during pregnancy and in the bloodstream of the mother there will be glucose, amino acids, fats- these will travel through her bloodstream and into the wall of the uterus- these molecules will cross into the child's blood into the placenta- which are then taken into the child.
-the placenta has a large surface area- barrier from mother and child's blood is very thin.
-the child also produces molecules that exchanges into the maternal blood like carbon dioxide and urea.

3.9b Female Reproductive System

recall the structure of and function of the female reproductive system.
-ovary-meiosis occurs, production of eggs (female gametes)
-oviducts- carries the egg to the uterus. also the location where fertilisation takes place. (sperm cell meets egg cell)
-uterus- structure in the center, it is made out of muscle, stretches to accommodate pregnancy and it contracts during birth.
-lining of the uterus- develops the fertilized egg into the embryo and then the child. you can also see the development of the placenta here.
-uterus space- is where the sperm and egg cells move. where the embryo develops into the unborn child.
-cervix- entrance to the uterus. where sperm cells enter will make their way to the oviducts.
-vagina- collects sperm cells and allow them to pass through the cervix into the uterus.  

3.9a Male Reproductive System

recall the structure and the function of the male reproductive system
-bladder- stores urine.
-testis- there is 2 of them- carries out the process of meiosis that produces the gamete called a sperm cell.
-epididymis- stores sperm cells.
-vas deferens- carries the sperm cell to the penis during sexual stimulation. the tube pulses making the walls contract pushing the sperm cells into the penis.
-prostate- adds about 20-30% of the volume of the semen. it contains sugar and is alkali.
-seminal vesicles- produce sugar based secretion, also alkali. 70% of the semen in which the sperm cell can travel.

-when sperm cells are combined with the prostate and the seminal vesicle secretions we have semen- carried forward and down to the urethra (common tube which joins the left and right testes and the left and right vas deferens)

-urethra- takes semen down the penis and the exit for the urine which is stored in the bladder.
-penis- carries sperm cell into the vagina during sexual intercourse.