How Can the Same Icts Used for the Multiple Purposes

NORTHERN MUSLIM SCHOOL

LIFE SCIENCES

GRADE 12 MARKS: 60

EXAMINER: MUTOYO E MODERATOR: MOOSA T

CONTROLLED TEST 1 TERM 1 2016

MEMORANDUM

DATE: 07 MARCH 2016

SECTION A

QUESTION 1

1.1.1 D√√ 2

1.1.2 A√√ 2

1.1.3 C√√ 2

1.2.1 Karyokinesis√

1.2.2 mRNA√

1.2.3 Cells of Leydig√ 3

1.3.1 B only√√ 2

1.3.2 A only 2

1.3.3 B only√√ 2

QUESTION 2

2.1 Chromosomes are arranged in homologous pairs at the equator√√ 2

2.2 Process is called crossing over√

Occurs in prophase 1 of meiosis√

Homologous chromosomes pair off√

Non-chromatids of each chromosome overlap√

Points of overlap are called chiasmata√

A break occurs at the chiasma√

Each chromosome now has genetic material from its homologue√ Any 4 4

2.3 Diagram I Anaphase I-whole chromosome move apart to the poles√

Diagram II Anaphase II-chromatids/daughter chromosomes of each chromosome move to the poles√ 2

2.4.1 Incidence of genetic abnormalities is affected by pollution√√√ 3

2.4.2 Independent variable-month√, Dependent variable-pollution levels√ 2

2.4.3 Information of whether the number of children born with genetic abnormalities increases/ decreases√ during the months when pollution levels are high√/They need to find out more about the type of pollutants in the air in this area√ that could cause genetic abnormalities√. 2

QUESTION 3

3.1.1 They decrease√ 1

3.1.2 Menstruation starts√ 1

3.1.3 They will increase√√ 2

3.1.4 (a) LH-ovulation√

(b) FSH-stimulates growth of graafian follicle√ 2

3.2 Mother-Not enough area for placenta/Suffer deformity/Tissue unsuitable√ 1

Foetus-Not enough space to grow/Suffer internal injury 1

3.3.1...