4HB0 Revision Notes

7/28/2019 4HB0 Revision Notes

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Role of tissue fluid (mark scheme ) : Four from:

Surrounds cells;

Carries food/oxygen to cells;

from capillaries/blood;

formed from plasma/under high pressure;

Carries carbon dioxide/(nitrogenous) waste from cells;

to lymph vessel/lymphatic system;

referred to as lymph;

tidal volume : the volume of air exchanged during quiet breathing in

one breath

vital capacity : the maximum volume of air that can be breathed in

one breath

mark scheme :

ABO :

O is universal donor;

Contains no antigens;

Donor A/person with blood group A contains A antigen;

Donor A/person with blood group A contains b antibody

Why someone with cystic fibrosis finds it hard to exercise :

Reference to mucus being thicker/sticker;

Idea of less oxygen into the body;

Reduced (aerobic) respiration;

Reference to not enough energy;

1 nerve cell (neurone) elongated part of cell (axon) for carrying nerve impulses. Dotted lines

indicate that axon is very long compared with the rest of the cell.


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2 smooth muscle cell from the wall of the intestine elongated, can contract to move food through the

gut.

3 ciliated epithelium cell lines passages such as the trachea (windpipe). The hair-like cilia beat to

move

mucus along the lining of the trachea.

4 white blood cell can change its shape to surround and destroy bacteria.

5 red blood cells contain haemoglobin to carry oxygen around the body.

6 sperm cell tail for swimming, head contains genes from the father.

breathing rate: the number of breaths taken in one minute

one of the factors that affect teeth growth is the presence of vitamins and minerals in diet such vitamin

D and calcium

other factors may be due to gender , systemic diseases , hormonal factors , height and weight

how to care for teeth and gums :

1. Brushing

2. Flossing

3. Eating right

4. Visiting the dentist

5. Rinsing

_ gonadtrophic hormones secreted by pituitary gland and which target is the gonads CONTROLS

REPRODUCTIVE ACTIVITY .

How the body removes CO2 and water from the body after respiration

CO2 is removed through the blood stream while water is used by the body

Blow into a balloon (a single normal exhalation, not forced) and then put a long ruler up beside it andmeasure the diameter of the balloon; note it down.

Now, do some exercise of your choice for about 2 minutes, then blow into the balloon (again - one single

normal exhalation, not forced) and measure the diameter; note this down.

Repeat this about 3-5 times to gain an average result.

Simple experiments on diffusion and osmosis using living and non-living systems


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(a) Cubes of agar jelly placed into solutions of methylene blue or potassium

permanganate will absorb the pigment by diffusion. The cubes are left in the

pigmented solution for different measured periods of time and are then sliced

open. The distance between the edge of each cube and the edge of the

coloured agar may be used as a measure of the distance the pigment

molecules have moved by diffusion.

(b) A crystal of potassium permanganate can be dropped into a beaker of water

and the appearance of the water noted over time.

(c) To demonstrate osmosis, Visking tubing (dialysis tubing) can be tied at one

end and filled with 20% sucrose solution. The other end is attached to a

capillary tube. The level of the sucrose can be noted before and after the

tubing has been placed in a beaker of water for about thirty minutes.

(d) Onion epidermis can be peeled away, cut into squares and mounted on slides

in different concentrations of sucrose solution. Observation under a

microscope will show the effects of osmosis.

(e) Red blood cells in blood obtained from a butcher may be mounted on slides in

hypotonic, isotonic and hypertonic saline, and observed under a microscope

to show the effects of osmosis.

(f) Osmosis can be demonstrated by using strips of potato, and this basic

experimental method provides a good opportunity for students to carry out

individual whole investigations. Because of the difficulty of the osmosis

concept, it is better to keep this investigation until the latter part of the course

so that students will have had previous experience of carrying out

investigations on simpler topics. Students enjoy the reference to chips, but

should quickly realise that it can be difficult to keep the size constant - to


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achieve consistency lengths of potato tissue can be drilled from a potato

using a cork borer. The chips are measured by mass or by length and are

placed into sucrose solutions of different concentrations for at least one hour.

The percentage change in mass or length is a measure of the degree of

osmosis that has occurred.

(g) A variation on this theme is to cut potato cubes of different sizes, which have

different surface area to volume ratios. After measuring and recording the

masses of the cubes, they are immersed in water. After one hour, the cubes

are blotted dry and their masses measured and recorded again. The

percentage increase in mass for cubes of different surface area to mass ratio

can be compared, to explore the concept of how surface area to volume ratio

influences water uptake.

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4HB0 Revision Notes