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)

Edit

Write in Short

Short Answer▾

State the names of four other groups of substances in a balanced diet.

Explanation

There are seven essential factors for a balanced diet: carbs, protein, fat, fiber, vitamins, minerals, and water.

There Are Seven Essential Factors for a Balanced Diet: Carbs, Protein, Fat, Fiber, Vitamins, Minerals, and Water
S. No.Nutrient% of daily caloriesFunctionSource
1Carbs45 – 55 %EnergyGrains (refined & unrefined) : wheat, maize, corn, millet, oats, rice, flour, pasta, noodles; potatoes; sweet potatoes, yam. Fruit (sugar) .
2Protein10 – 35 %Tissue growth and maintenanceMeat, fish, nuts, eggs, soya, beans, and pulses.
3Fat20 – 35 % from fatEnergy, energy storage, hormone productionNuts, seeds, plant oils, dairy products (milk, cheese) .
4FiberIncluded in carbs.Regulates blood sugar levels, bowel function and bowel health.Peas, beans, vegetables, fruit, oats, whole grains, brown rice, nuts, seeds.
5Vitamins & mineralstraceMetabolism regulation, aiding cell growth, other biochemical functionsSpecific to each vitamin/mineral. A range of vegetables, lean meat, nuts and seeds will cover most people՚s needs.
6Water0Maintaining hydrationDrinking water, other beverages. About 20 % of water intake comes from food.

Developed by: