IGCSE Biology Paper-3: Specimen Questions with Answers 354 - 355 of 358

Passage

The blood of a fetus does not mix with the blood of its mother, but substances are exchanged across the placenta.

Question 354 (4 of 4 Based on Passage)

Write in Short

Short Answer▾

Table 17.1 shows five substances that cross the placenta, their direction of movement and the reason for the movement.

Complete Table 17.1.

Five Substances That Cross the Placenta, Their Direction of Movement and the Reason for the Movement
substancedirection of movementreason
oxygen
glucose
urea
amino acid
carbon dioxidefrom fetuswaste gas from respiration

Explanation

Five Substances That Cross the Placenta, Their Direction of Movement and the Reason for the Movement
substancedirection of movementreason
oxygentowards fetusFor respiration
glucosetowards fetusFor respiration
ureafrom fetusWaste from metabolic processes
amino acidfrom fetuswaste from metabolic processes
carbon dioxidefrom fetuswaste gas from respiration

Passage

A balanced diet contains seven different groups of substances.

Three of these groups of substances are fats, fiber (roughage) and vitamins.

Question 355 (1 of 2 Based on Passage)

Write in Short

Short Answer▾

The boxes on the left contain the names of conditions that can develop if the diet is not balanced for a long period of time.

The boxes on the right contain descriptions of how these conditions may be caused.

Draw one straight line from each box on the left to a box on the right to link the condition to its cause.

Description of Cause

Explanation

Description of Cause

Eating more calories than you burn in daily activity and exercise on a long-term basis can lead to obesity.

Common lifestyle causes of constipation include:

  • Eating foods low in fiber.
  • Not drinking enough water (dehydration) .
  • Not getting enough exercise.
  • Changes in your regular routine, such as traveling or eating or going to bed at different times.
    • Starvation is a severe deficiency in caloric energy intake, below the level needed to maintain an organism՚s life. It is the most extreme form of malnutrition. In humans, prolonged starvation can cause permanent organ damage and eventually, death.
    • Scurvy is a disease resulting from a lack of vitamin C (ascorbic acid) . Early symptoms of deficiency include weakness, feeling tired and sore arms and legs. Without treatment, decreased red blood cells, gum disease, changes to hair, and bleeding from the skin may occur.

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