Biology (Human body)

What do chromosomes contain?

Genes made of DNA

What is fertilisation?

When a sperm cell joins with an egg cell

Why are egg cells generally larger than sperm cells?

Egg cells contain food reserves

How many chromosomes does a human have?

46

How can smoking affect the fetal development by the mother?

It can cause miscarriage or still birth, premature baby, low birthweight, sudden infant death syndrome (SIDS) increased chance of developing breathing problems

What can drugs like cocaine and heroin cause?

Miscarriage or still birth and premature baby

Why is protein needed for the fetus?

Protein is needed to help the fetus grow and produce new cells

Why is carbohydrates needed for the fetus?

Carbohydrates provide energy to the cells

Why is iron needed for the fetus and the mother?

Iron is needed to make haemoglobin

Why is calcium needed for the baby and the mother?

Calcium is needed to help the baby grow strong bones and keep the mother’s bones and teeth healthy

What is sex inheritance?

Where the baby’s gender is determined either by the X and Y chromosomes from its parents

XX and XY chromosomes

XX = Girl

XY = Boy

Why are gender chances 50%?

A sperm cell has either an XX or XY sex chromosome

What is variation?

Differences between individuals belonging to the same species

Causes of variation

DNA (Genes), Environment

What a genetic differences

Differences in the DNA organisms belonging to the same species

Why won’t the offspring look identical to its parents?

When a sperm cell fuses with an egg cell, the zygote produces a new combination of DNA

Why do animals of the same species look different?

Different genetic material, Different parents

What would happen to the population of a species when there is an environmental change?

The population can go extinct