B3 Quiz

Osmosis is the movement of [blank_start]water molecules[blank_end] across a [blank_start]partially permeable membrane[blank_end] from an area of high concentration to an area of low concentration.

In the body, how does osmosis work within cells?

Active transport is the movement of substances against a concentration gradient.

In root hair cells, the concentration of minerals is usually higher in the cell than in the soil surrounding it. Active transport allows the plant to absorb minerals from a very dilute solution. This is essential for the plant [blank_start]to grow.[blank_end]

When there's a higher concentration of glucose and amino acids in the gut they diffuse naturally [blank_start]into the blood[blank_end]. If there is a lower concentration of nutrients in the [blank_start]blood[blank_end] than in the [blank_start]gut[blank_end], active transport is necessary to [blank_start]prevent us from starving.[blank_end]

How are exchange surfaces adapted?

Active transport is a passive process.

In leaves, carbon dioxide diffuses into the air spaces within the leaf and then into the cells in which [blank_start]photosynthesis[blank_end] happens. The cell walls increase [blank_start]surface area[blank_end] so carbon dioxide is more likely to get through. The bottom of the leaf is covered in [blank_start]stomata[blank_end] which the carbon dioxide diffuses through. Leaves are flat to [blank_start]increase[blank_end] this exchange surface area. Guard cells close the stomata if water is being [blank_start]lost too quickly[blank_end]. [blank_start]Oxygen and water[blank_end] diffuse out through the stomata. Water vapour evaporates from leaf cells and escapes by diffusion.

Label the respiratory system.

What happens when you breathe in?

What happens when you breathe out?

Artificial ventilators pump air out of the case causing pressure to drop, lungs to expand and air to be drawn in.

New ventilators pump air into the lungs causing the ribcage to expand, air to be drawn in. To breathe out, the ribcage relaxes.

Which system could interfere with blood flow to the lower body?

[blank_start]New ventilators[blank_end] could cause damage, for example they could burst alveoli, if the lungs can't cope with artificial air flow.

The alveoli are small air sacs inside your [blank_start]lungs[blank_end]. Inside them, gas exchange takes place wherein [blank_start]oxygen[blank_end] is transferred to the blood and [blank_start]carbon dioxide[blank_end] is removed. They are adapted for efficient diffusion as they have a large [blank_start]surface area[blank_end], moist [blank_start]lining[blank_end], [blank_start]thin[blank_end] walls and good [blank_start]blood[blank_end] supply.

The small intestine is covered in millions of projections called [blank_start]villi[blank_end]. They increase the small intestine's [blank_start]surface area[blank_end] in order to speed up [blank_start]digestion[blank_end]. The have a [blank_start]single[blank_end] layer of surface cells so there isn't long for food to diffuse through, and a good [blank_start]blood supply[blank_end] for quick absorption.

Which plant vessel is made of columns of living cells that transports food from leaves to growing regions and storage organs in both directions?

Xylem vessels are dead cells joined end to end with no middle that carry water and minerals from the roots to the stem and leaves in the transpiration stream.

What is transpiration?

The transpiration stream happens through [blank_start]xylem[blank_end] vessels when there is a [blank_start]water[blank_end] shortage in a plant and it is therefore necessary for these vessels to replace it.

Describe the double circulatory system: [blank_start]Deoxygenated[blank_end] blood is pumped to the lungs to receive [blank_start]oxygen[blank_end]. The newly [blank_start]oxygenated[blank_end] blood returns to the heart. This oxygenated blood is pumped to [blank_start]all other body organs[blank_end]. It gives up its oxygen at the [blank_start]body[blank_end] cells and becomes [blank_start]deoxygenated[blank_end]. The system repeats in a cycle.

How does the heart work? Blood flows into the [blank_start]atria[blank_end] from the [blank_start]vena cava[blank_end] and the [blank_start]pulmonary vein[blank_end]. The [blank_start]atria[blank_end] contract which pushes blood into the [blank_start]ventricle[blank_end]. The [blank_start]ventricles[blank_end] contract which forces blood into the [blank_start]pulmonary artery[blank_end] and the [blank_start]aorta[blank_end] and out of the [blank_start]heart[blank_end]. Blood flows to organs through [blank_start]arteries[blank_end]. Blood returns to the heart through [blank_start]veins[blank_end]. The [blank_start]atria[blank_end] fill again and the cycle repeats.

Which blood vessel has thick layers of muscle for strong walls due to high blood pressure, as well as elastic fibres for this same reason? Hint: it carries blood away from the heart.

Which blood vessel supplies food/oxygen to your cells whilst removing waste like carbon dioxide, all by diffusion? Hint: it has permeable walls and is usually only one cell thick.

Which blood vessel has low blood pressure so has walls which aren't very thick, but despite this has a big lumen to help the blood flow through? Hint: it takes blood back to the heart and contains valves so blood flows in the right direction.

Red blood cells carry oxygen from the lungs to all other cells in your body, so the more you've got, the more oxygen can get to your cells. How are red blood cells adapted for their function?

White blood cells have a nucleus. How do they defend against disease?

Platelets are small fragments of cells without a nucleus. They help to clot your blood. What can a lack of platelets in your blood lead to?

Plasma carries a lot of stuff in your blood. It is a pale straw coloured liquid. What does it carry?

What is the purpose of artificial blood?

Artificial blood is often used in [blank_start]emergency[blank_end] situations wherein a patient is [blank_start]losing[blank_end] a lot of blood. It buys the patient time to produce new [blank_start]blood cells[blank_end] so the heart can continue pumping. It is relatively safe, as long as there are no [blank_start]air bubbles[blank_end] present in the artificial blood.

Sometimes patients need to receive an artificial heart. Tick what is correct.

Deffective heart valves can be replaced with [blank_start]mechanical valves[blank_end]. Although it is a less drastic procedure than a [blank_start]heart[blank_end] transplant, it is still major surgery and there is a risk of [blank_start]blood clots[blank_end].

[blank_start]Stents[blank_end] are tubes inserted into the arteries to keep blocked arteries open so [blank_start]blood[blank_end] can pass through and the heart can continue beating. They are used to prevent heart attacks in people with [blank_start]coronary heart[blank_end] disease (fatty deposits blocking arteries) however if [blank_start]scar tissue[blank_end] forms due to stent irritation, the artery can narrow again. Drugs are needed to prevent [blank_start]blood clots[blank_end].

Homeostasis is the maintenance of [blank_start]a constant internal environment[blank_end].

Homeostasis controls many things in your internal body environment, including temperature. Tick the boxes that describe what happens when your body gets too hot. Do not tick the boxes that describe what happens when your body gets too cold.

Homeostasis maintains a constant internal environment in your body by controlling the following six things. What do the kidneys do in relation?

Your kidneys regulate the water content in your body. Water is taken in by [blank_start]food[blank_end] and [blank_start]drink[blank_end], and lost in [blank_start]urine[blank_end], [blank_start]sweat[blank_end] and the air we breathe out. On a cold day you don't sweat so you produce [blank_start]more[blank_end] urine which is [blank_start]pale[blank_end] and [blank_start]dilute[blank_end]. On a hot day you do sweat so you produce [blank_start]less[blank_end] urine which is [blank_start]dark coloured[blank_end] and [blank_start]concentrated[blank_end].

Your kidneys regulate the ion content in your body. Ions are taken in in [blank_start]food[blank_end] and absorbed into the [blank_start]blood[blank_end]. If there is an incorrect balance of water and ions in your body, the wrong amount of water will be drawn into your cells by [blank_start]osmosis[blank_end] which can [blank_start]damage[blank_end] your cells or make them not work as well. Your kidneys remove excess sodium from the [blank_start]blood[blank_end]. Some ions are lost in [blank_start]sweat[blank_end].

Your kidneys remove urea from your body. Urea is produced as a waste product in the reaction of [blank_start]proteins[blank_end] being converted to [blank_start]fats[blank_end] and [blank_start]carbohydrates[blank_end] to be stored. This reaction takes place in the [blank_start]liver[blank_end]. Urea is poisonous. The [blank_start]liver[blank_end] first releases it into the [blank_start]bloodstream[blank_end], then the kidneys filter out the [blank_start]blood[blank_end] and temporarily store it in the [blank_start]bladder[blank_end] in urine to be excreted from the body.

[blank_start]Nephrons[blank_end] are the filtration units in the kidneys.

The kidneys act as a filter in three stages. These are [blank_start]ultrafiltration[blank_end], [blank_start]reabsorption[blank_end] and the [blank_start]release of wastes[blank_end].

During filtration, a high pressure squeezes water, [blank_start]urea[blank_end], [blank_start]ions[blank_end] and sugar out of the blood and into the [blank_start]Bowman's capsule[blank_end]. [blank_start]Big[blank_end] molecules cannot get through so proteins and blood cells stay in the blood.

During reabsorption, [blank_start]useful[blank_end] substances are reabsorbed into the blood. These include all [blank_start]sugars[blank_end] and sufficient [blank_start]ions[blank_end] (both by [blank_start]active transport[blank_end]), as well as sufficient [blank_start]water[blank_end].

During the release of wastes in the kidneys, [blank_start]remaining[blank_end] substances (including [blank_start]urea[blank_end]) continue out the nephron, into the ureter and down to the bladder as [blank_start]urine[blank_end].

Dialysis is one way to treat kidney failure. The person's blood flows along a [blank_start]selectively permeable[blank_end] barrier surrounded by dialysis fluid. It acts like the [blank_start]membranes[blank_end] in the kidneys by being permeable to things like [blank_start]ions[blank_end] and waste substances, but not allowing [blank_start]big[blank_end] molecules through. Dissolved ions and glucose aren't lost from the blood during dialysis because the dialysis fluid has the [blank_start]same[blank_end] concentration of them as healthy blood. Waste substances and excess ions/water can [blank_start]diffuse[blank_end] across the barrier. Although this saves lives, it's a hassle as patients go three times a week for hours. Dialysis can cause [blank_start]blood clots[blank_end] or infections.

A kidney transplant will [blank_start]cure[blank_end] kidney failure. A donor who has died suddenly or is on the organ donor register gives a healthy kidney to a patient with kidney failure. The donor kidney could be [blank_start]rejected[blank_end] by the patient's immune system as the patient's [blank_start]antibodies[blank_end] attack the donor kidney's foreign [blank_start]antigens[blank_end]. This can be prevented if the donor's tissue type [blank_start]closely matches[blank_end] the patient's tissue type, or if the patient takes [blank_start]immune-suppressing drugs[blank_end]. These make them [blank_start]more[blank_end] susceptible to illness. Dialysis [blank_start]is not[blank_end] necessary with a kidney transplant.

What removes blood glucose from the blood? If not ticked, it adds glucose the blood.

What happens when the blood glucose level is too high?

When the blood glucose level is too high, [blank_start]insulin[blank_end] is secreted by the [blank_start]pancreas[blank_end]. Glucose is therefore [blank_start]removed[blank_end] by the [blank_start]liver[blank_end] as insulin caused the [blank_start]liver[blank_end] to turn [blank_start]glucose[blank_end] into [blank_start]glycogen[blank_end].

When the blood glucose level is too low, [blank_start]glucagon[blank_end] is secreted by the pancreas. Glucose is therefore [blank_start]added[blank_end] by the liver as [blank_start]glucagon[blank_end] caused the liver to turn [blank_start]glycogen[blank_end] into [blank_start]glucose[blank_end].

Type 1 Diabetes is caused when the pancreas doesn't produce enough [blank_start]insulin[blank_end] so blood glucose levels can [blank_start]rise[blank_end] to a deathly level.

How can we control Type 1 Diabetes?