SB2 Cells and Control

Question 1

What is Mitosis?

Answer 1

The cell divides to make 2 genetically identical daughter cells and it consists of 4 stages, Prophase, metaphase, Anaphase and Telophase. Prophase being the first stage the membrane around the nucleus. starts to disappear. The Metaphase stage is where the chromosomes and their copies line up in the middle of the cell. Anaphase is the stage where the chromosomes and their copies are pulled to the different ends of the cell. Telophase is the stage where new membranes form around the chromosomes

Question 2

What is Meiosis?

Answer 2

Meiosis, similarly with Mitosis is where a cell divides and splits it chromosomes into 2 genetically identical daughter cells each with 23 chromosomes (the original cell containing 46 chromosomes) the phases of Meiosis are very similar to that of mitosis with them being Prophase, metaphase, Anaphase and Telophase. Prophase being the first stage the membrane around the nucleus. starts to disappear. The Metaphase stage is where the chromosomes and their copies line up in the middle of the cell. Anaphase is the stage where the chromosomes and their copies are pulled to the different ends of the cell. Telophase is the stage where new membranes form around the chromosomes

Question 3

Define what is a percentile growth curve.

Answer 3

A percentile growth chart can be used to track and assess the growth of an organism over time. If a child is in the 20th percentile at birth for their mass this means that they weight more than 20% of all babies at that age, but 80% of babies weight more than them. If a baby is in the 89th percentile, the baby weight more than 89% of babies at that age and 11% of all babies weight more than them. Percentile or growth charts can be used to monitor if a child is growing normally. If they are in 99th percentile for head circumference, but the 3rd percentile for height this means that the baby’s head is bigger than 99% of the rest of the worlds babies. This also means that their height is less than 97% of babies indicating dwarfism.

Question 4

What are stem cells?

Answer 4

Stem cells are specialized cells that can be differentiated into different types of cells. There are 2 major types of stem cells, Embryonic and Adult stem cells, embryonic stem cells are usually better for use in a human body because there is less of a chance of the body rejecting it, since it came from their body originally, whilst adult stem cells can often get rejected from the body.

Question 5

Explain the function of the cerebral cortex in the brain.

Answer 5

The cerebral cortex is where consciousness and thinking, personality and emotion come from. It is located at the top of the brain.

Question 6

Explain the function of the Cerebellum in the brain

Answer 6

The cerebellum controls balance and movement for the body, it is located on the bottom right of the brain.

Question 7

Explain the function of the Spinal chord in the brain.

Answer 7

The spinal chord is the link between the brain and the nervous system, it is located at the very bottom of the brain.

Question 8

Explain the function of the Medulla oblongata in the brain.

Answer 8

The medulla oblongata controls unconscious things in the brain such as heart rate of breathing. It is located in the lower brain.

Question 9

Explain the function of the pituitary gland in the brain.

Answer 9

The pituitary gland is responsible for regulating all the hormones in the body. It is located toward the bottom part of the brain.

Question 10

Explain the function of the hypothalamus in the brain.

Answer 10

The hypothalamus is the part of the brain that controls your body temperature to keep it within normal levels. It is located near the middle of your brain.

Question 11

What type of cells is the brain predominantly made out off?

Answer 11

Nerve cells.

Question 12

Identify and explain the types of scan for the brain.

Answer 12

The 2 types of scans for the brain are the PET scan and the CT scan, the PET scan is where they inject miniscule radioactive tracers into the blood stream where it can be tracked throughout the brain. Gamma rays are released from the radioactive source, as the gamma rays are released, they are detectors in the PET scanner. The second type of scan is called the CT scan which is where Xray radiation is fired at the brain in many different directions in order to produce a 3D image of the brain, this is not recommended for children, pregnant women or elder people due to the high amount of xray radiation being emitted.

Question 13

What is the difference between a Haploid and a Diploid cell?

Answer 13

Haploid cells contain only 1 set of chromosomes whilst Diploid cells contains 2 sets of chromosomes.

Question 14

Identify and explain the 3 different types of Neurones.

Answer 14

The first neurone is called the sensory neurone, the second is called the relay neurone and the final neurone is called the motor neurone. The sensory neurone is responsible for detecting the stimulus and sending an impulse to the spinal chord, after this the relay neurone will get the impulse from the spinal chord. The relay neurone will continue and relay the impulse to the motor neurone where it will there send the impulse back to the effector and contract its muscles.

Question 15

Give an example of 3 receptors.

Answer 15

Eyes, ears and skin, the eyes can detect a change in light, ears can detect a change in sound and the skin can detect a change in touch.

Question 16

Describe the optic nerve.

Answer 16

Carry the impulse from the optic nerve to the brain and tells the brain what kind of light there and then the brain allows us to tell what we are seeing

Question 17

Describe the Cornea

Answer 17

Transparent cuved part of the eye in front, allows you to refract the eye and makes it goes to the back of the eye to the retina

Question 18

Describe the Iris

Answer 18

Circular and radial muscles, and controls the size of the pupils, colored part of your eye.

Question 19

Describe the pupil

Answer 19

The black bit in the eye, determines how much light can enter the eye.

Question 20

Describe the lens

Answer 20

Focuses distances

Question 21

Describe the ciliary muscles

Answer 21

Changing the shape of the lens

Question 22

Describe the Retina

Answer 22

Is made up of cones and rods

Question 23

What are Cone and Rod cells in the eye.

Answer 23

Cones are receptor cells that are sensitive to the Colour of light, some cones detect red light whilst other detect blue or green light. Cones can only work when there is bright light
Rods are a kind of photo receptor, they don’t detect color, they detect light intensity

Question 24

Identify and describe the 4 most common eye conditions

Answer 24

Long/short sightedness, cataracts, color blindness, Long and short sightedness is where you can only see either really close or really far, this is due to the eyeball being too short or too long. Cataracts is where protein starts to buildup in your eyes, it can cause blurry vision. Finally color blindness is where the cone and rod cells do not work and you may not see colors or you may just see different colors.

Question 25

What is the difference between asexual and sexual reproduction?

Answer 25

In sexual reproduction, an organism combines the genetic information from each of its parents and is genetically unique. In asexual reproduction, one parent copies itself to form a genetically identical offspring. This means that asexual reproduction usually only requires 1 parent and not very much energy whilst sexual reproduction requires quite a lot of energy as well as takes a lot of time.