Graad 12:

1. DNS
 Ligging
 Struktuur
 Ontdekking (Watson, Crick, Franklin en Wilkens)
 Rol van DNS (gene en nie-koderende DNS)
 DNS-replisering

2. RNS
 Tipes RNS en hull igging in die sel
 Struktuur
 Transkripsie
 Translasie (Proteïensintese)
 Genetiese kode
 DNS-vingerafdrukke

3. Meiose
 Proses (reduksiedeling)
 Doel van reduksiedeling
 Belangrikheid van meiose
 Genetiese variasie (willekeurige segregasie en oorkruising)
 Abnormale meiose (downsindroom)
 Ooreenkomste en verskille tissen mitose en meiose

4. Diversiteit van voortplantingstrategieë by gewerwelde diere

 Soorte bevrugting (inwendig en uitwendig)
 Ontwikkeling van embrio
 Amniotiese eier
 Prekosiale en altrisiële ontwikkeling
 Ouerlike sorg

5. Struktuur van manlike en vroulike voortplantingstelsel

 Manlike en vroulike orgaan
 Puberteit
 Gametogenese en meiose
 Menstruele siklus en hormonale beheer
 Bevrugting en ontwikkeling van sigoot en blastosist
 Gestasie (draagtyd)
 Implantasie en embrioniese ontwikkeling (rol van plasenta)

6. Genetika
 Gene
 Dominante en ressesiewe allele
 Gregor Mendel
 Mono-en dihibriede kruisings
 Geslagsverwant allele en siektes
 Mutasies
 Genetiese manupilering
 Mitochondriese DNS
 7. Senuweestelsel
 Brein (struktuur en funksie)
 Reaksie op stimuli
 Sentrale senuweestelsel
 Perifere senuweestelsel
 Outonome senustelsel
 Senuwee (bou)
 Refleksboog (bou, funksie en belngrikheid)
 Oordrag van impulse
 Alzheimer en Veelvoudige sklerose
 Oog (bou en werking, akkomodasie en pupilmeganisme en gesigsgebreke)
 Oor (bou, werking, gehoor, balaas)
 Revision of the structure of the cell with an emphasis on the ribosome, cytoplasm and parts of the nucleus
 Nucleic acids consist of nucleotides
 Two types of nucleic acids are DNA and RNA

 Location of DNA
 Makes up the genes on chromosomes
(nuclear DNA)
 Present in mitochondria (mitochondrial DNA)

 Brief history of the discovery of the structure of the DNA molecule (Watson & Crick, Franklin & Wilkins)

 Three components of a DNA nucleotide:

 Nitrogenous bases linked by weak hydrogen
bonds
 4 nitrogenous bases of DNA: adenine (A), thymine (T), cytosine (C), guanine (G)
 Pairing of bases in DNA occur as follows A : T and G : C
 Sugar portion (deoxyribose in DNA)
 Phosphate portion

 The natural shape of the DNA molecule is a double helix

DNA:
The code of Life
 Stick diagram of DNA molecule to illustrate its structure

 Functions of DNA:
 Sections of DNA forming genes carry
hereditary information
 DNA contains coded information for protein
synthesis

 Process of DNA replication:

 When in the cell cycle it takes place
 Where in the cell it takes place
 How DNA replication takes place (names of
enzymes not required)
 The significance of DNA replication

 Definition of DNA profile

 Uses of DNA profiles
 Interpretation of DNA profiles

Practical Worksheet 1
 Location of RNA:
 mRNA is formed in the nucleus and functions
at the ribosome
 tRNA is located in the cytoplasm

 RNA plays a role in protein synthesis

 Structure of RNA:
 A single stranded molecule consisting of
RNA nucleotides
 Each nucleotide is made up of a sugar
(ribose), phosphate and a nitrogen base
 4 nitrogenous bases of RNA are: adenine
(A), uracil (U), cytosine (C), guanine (G)
  Stick diagram of mRNA and tRNA molecules to illustrate their structure
 The involvement of DNA and RNA in protein synthesis:
 Transcription
 The double helix DNA unwinds
 The double-stranded DNA unzips/weak hydrogen bonds break
 to form two separate strands.
 One strand is used as a template
 to form mRNA
 using free RNA nucleotides from the nucleoplasm.
 The mRNA is complementary to the DNA.
 mRNA now has the coded message for protein synthesis.

 mRNA moves from the nucleus to the

cytoplasm and attaches to the ribosome.

 Translation
 Each tRNA carries a specific amino acid.
 When the anticodon on the tRNA
 matches the codon on the mRNA
 then tRNA brings the required amino acid to the ribosome. (Names of specific codons, anticodons and
their amino acids are not to be memorised)
 Amino acids become attached by peptide bonds
 to form the required protein.

Simple diagram to illustrate transcription and translation in protein synthesis

Meiosis  Revision of the structure of a cell with an emphasis on the parts of the nucleus, the centrosome and the
cytoplasm

 Structure of chromosomes:
 Chromosomes consists of DNA (which
makes up genes) and protein
 The number of chromosomes in a cell is a
characteristic of an organism (for example
humans have 46 chromosomes)
 Chromosomes which are single threads,
become double (two chromatids joined by a
centromere) as a result of DNA replication

 Differences between:
 Haploid(n) and diploid(2n) cells in terms of
chromosome number
 Sex cells (gametes) and somatic cells (body
cells)
 Sex chromosomes (gonosomes) and
autosomes

 Revision of the process of mitosis

 Definition of meiosis
 Site of meiosis in plants and in animals
 Meiosis is a continuous process but the events are divided into different phases for convenience
 Events of interphase:
 DNA replication takes place
 Chromosomes which are single threads,
become double
 Each chromosome will now consist of two
chromatids joined by a centromere
 DNA replication helps to double the genetic
material so that it can be shared equally by
the new cells arising from cell division

 The events of the following phases of Meiosis I, using diagrams:

 Prophase I
 including a description of crossing-over
 Metaphase I
 including the random arrangement of chromosomes
 Anaphase I
 Telophase I
  The events of each phase of Meiosis II, using diagrams:
 Prophase II
 Metaphase II
 Anaphase II
 Telophase II

 The importance of meiosis:

 Production of haploid gametes
 The halving effect of meiosis overcomes the
doubling effect of fertilisation, thus
maintaining a constant chromosome number
from one generation to the next.
 Mechanism to introduce genetic variation
through:
 Crossing-over
 The random arrangement of
chromosomes at the equator

 Non-disjunction and its consequences

 Non-disjunction of chromosome pair 21 during anaphase I in humans to form abnormal gametes with an extra
copy of chromosome 21
 The fusion between an abnormal gamete (24 chromosomes) and a normal gamete (23 chromosomes) may
lead to Down syndrome

 Similarities in mitosis and meiosis

 Differences between mitosis and meiosis
Practical Worksheet 2
SBA Practical task 1: Meiois
Diversity of reproductive strategies
 The role of the following reproductive strategies in animals in maximizing reproductive success in different
environments (using relevant examples):
Reproduction in  External or internal fertilisation
Vertebrates  Ovipary, ovovivipary, vivipary
 Amniotic egg
 Precocial and altricial development
 Parental care
 Revision of the schematic outline of the human life cycle to show the role of meiosis, mitosis and fertilisation

 Structure of the male reproductive system, using a diagram

 Functions of the testis, epididymis, vas deferens, seminal vesicle, prostate gland, Cowper’s gland and the
urethra

 Structure of the female reproductive system, using a diagram

Human  Functions of the ovary; Fallopian tubes; uterus lined by endometrium; cervix; vagina and its external opening;
reproduction and the vulva
 Structure of the ovary, using a diagram - showing the primary follicles, the Graafian follicle and the corpus
luteum

 The main changes that occur in male characteristics during puberty under the influence of testosterone
 Main changes that occur in female characteristics during puberty under the influence of oestrogen

Practical Worksheet 3
 Formation of gametes (gametogenesis) by meiosis.
 Male gametes formed by spermatogenesis
 Female gametes formed by oogenesis

 Spermatogenesis:
 Under the influence of testosterone
 diploid cells in the seminiferous tubules of
the testes undergo meiosis
 to form haploid sperm cells
 Structure of a sperm, using a diagram

 Functions of the parts of a sperm cell (acrosome, head with haploid nucleus, middle portion/neck with
mitochondria, and a tail)

 Oogenesis:
 Under the influence of FSH
 diploid cells in the ovary undergo mitosis
 to form numerous follicles
 One cell inside a follicle enlarges and
undergoes meiosis
 Of the four cells that are produced, only one
survives to form a mature, haploid ovum
  Structure of an ovum, using a diagram

 Functions of the different parts of an ovum (layer of jelly, haploid nucleus, cytoplasm)

 Menstrual Cycle:
 The menstrual cycle includes the uterine and ovarian cycles

 The events in the ovarian cycle

 Development of the Graafian follicle
 Ovulation
 Formation of the corpus luteum

 The events in the uterine cycle

 Changes that take place in the thickness of
the endometrium
 Menstruation

 Hormonal control of the menstrual cycle (ovarian and uterine cycles) with reference to the action of FSH,
oestrogen, LH and progesterone

 Negative feedback mechanism involving FSH and progesterone in controlling the production of ova

 Definition of copulation and fertilisation

 Process of fertilisation

 Development of zygote  embryo (morula and blastula/blastocyst)  foetus

 Definition of implantation

 The role of oestrogen and progesterone in maintaining pregnancy

 Structure of the developing foetus in the uterus, using a diagram

 Functions of the following parts:

 Chorion and chorionic villi
 Amnion, amniotic cavity and amniotic fluid
 Umbilical cord (including umbilical artery
and umbilical vein)
 Placenta
Practical Worksheet 4
Practical Worksheet 5
SBA task – Assignment (to be recorded in term 3)
 Introduction: Mention of Mendel as the father of genetics
 Concepts in inheritance:
 Chromatin and chromosomes
 Genes and alleles
 Dominant and recessive alleles
 Phenotype and genotype
 Homozygous and heterozygous

Monohybrid crosses:
 Format for representing a genetics cross
 Mendel’s ‘Principle of Segregation’
 Types of Dominance
 Complete dominance – one allele is dominant and the other is recessive, such that the effect of the recessive
allele is masked by the dominant allele in the heterozygous condition
Genetics and  Incomplete dominance – none of the two alleles of a gene are dominant over one another resulting in an
inheritance intermediate phenotype in the heterozygous condition
 Co-dominance – both alleles of a gene are equally dominant whereby both alleles express themselves in the
phenotype in the heterozygous condition
 Genetics problems involving each of the three types of dominance
 Proportion and ratio of genotypes and phenotypes
Sex determination
 22 pairs of chromosomes in humans are autosomes and 1 pair of chromosomes are sex
chromosomes/gonosomes
 Males have XY chromosomes and females have XX chromosomes
 Representation of a genetic cross to show the inheritance of sex

Sex-linked Inheritance
 Sex-linked alleles and sex-linked disorders
 Genetics problems involving the following sex-linked disorders:
 Haemophilia
 Colour blindness

Blood grouping
 Different blood groups are a result of multiple alleles
 The alleles IA, IB and i in different combinations, result in 4 blood groups
 Genetics problems involving the inheritance of blood type
 TERM 2

completion% SBA

tion% Comple-
Formal

Strand
Week
Date Topic Content assessme Date
nt plan

02/04 – 11 Dihybrid crosses

05/04  Mendel’s ‘Principle of Independent Assortment’
(4 days)  Dihybrid genetics problems Practical
 Determination of the proportion/ratio of genotypes task
and phenotypes Date……
…………
44
Genetic lineages/pedigree
 A genetic lineage/pedigree traces the the
inheritance of characteristics over many Test
generations Date……
 Interpretation of pedigree diagrams ………….

08/04 – 12 Genetics and Mutations Midyear 48

exam
Life at Molecular , Cellular & Tissue level

12/04 inheritance  Definition of a mutation

 Effects of mutations: harmful mutations, harmless Date
mutations and useful mutations ……………
 Mutations contribute to genetic variation
 Definition of gene mutation and chromosomal
mutation
 Mutations lead to altered characteristics in each
of the following genetic disorders:
 Haemophilia – due to absence of blood
clotting factors
 Colour blindness – due to absence of the
proteins that comprise either the red or green
cones/photoreceptors in the eye
 Down syndrome – due to an extra copy of
chromosome 21 as a result of non-
disjunction during meiosis

Genetic Engineering
 Genetic engineering uses biotechnology to satisfy
human needs:
 Stem cell research - sources and uses of
stem cells
 Genetically modified organisms – brief
outline of process (names of enzymes
involved are not required) and benefits of
genetic modification
 Cloning – brief outline of process and
benefits of cloning

Paternity testing
 The role of each of the following in paternity
testing:
 Blood grouping
 DNA profiles

Genetic Links
 Mutations in mitochondrial DNA used in tracing
female ancestry

SBA Practical Task 2: Genetics and Heredity 33

 Life processes in Plants & Animals
15/04 – 13 Responding to Introduction
18/04 environment  The nervous system (involving nerves) and
(4 days) endocrine system (involving hormones) are two
components that help us respond to the
environment

Human nervous system

 The need for a nervous system in humans:
 Reaction to stimuli (stimuli can be external
and internal)
 Co-ordination of the various activities of the
body

Central Nervous System:

 The brain and spinal cord are protected by
meninges

 Location and functions of the following parts:

 Brain
 Cerebrum
 Cerebellum
 Corpus callosum 52
 Medulla oblongata
 Spinal cord

Peripheral Nervous System:

 Location and functions of the peripheral nervous
system (cranial and spinal nerves)

Autonomic Nervous System:

 Location and functions of the autonomic nervous
system (sympathetic and parasympathetic
sections)

Structure and functioning of a nerve:

 Functions of sensory and motor neurons
 Structure and functions of parts of sensory and
motor neurons, using diagrams: nucleus, cell
body, cytoplasm, myelin sheath, axon and
dendrites

23/04 – 14 Reflex arc:

26/04  Definition of reflex action and a reflex arc
(4 days)  Structure of a reflex arc and functions of each
part, using a diagram: receptor, sensory neuron,
dorsal root of spinal nerve, spinal cord, inter-
neuron, motor neuron, ventral root of spinal
nerve, effector
 Functioning of a simple reflex action, using an
example
56
 Significance of a reflex action
 Significance of synapses

Disorders of the CNS

 Causes and symptoms of the following disorders
of the nervous system:
 Alzheimer’s disease
 Multiple sclerosis
Practical worksheet 6
29/04 – 15 Receptors 60
03/05  Functions of receptors, neurons and effectors in
(4 days) responding to the environment

 The body responds to a variety of different stimuli

such as light, sound, touch, temperature,
pressure, pain and chemicals (taste and smell).
(No structure and names necessary except for
names of the receptors in the eye and ear).

Human eye
 Structure and functions of the parts of the human
eye, using a diagram
  Binocular vision and its importance

 The changes that occur in the human eye for

each of the following, using diagrams:
 Accommodation
 Pupillary mechanism

 The nature and treatment of the following visual

defects, using diagrams:
 Short-sightedness
 Long-sightedness
 Astigmatism
 Cataracts
Practical worksheet 7

06/05 – 16 Human Ear

10/05  Structure of the human ear and the functions of
the different parts, using a diagram

 Functioning of the human ear in:

 Hearing (include the role of the organ of Corti
without details of its structure)
 Balance (include the role of maculae and cristae
without details of their structure)

 Cause and treatment of the following hearing

defects:
 Middle ear infections (Use of grommets)
 Deafness (Use of hearing aids and cochlear
implants)
SBA Assignment (Recorded in term 3)

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