Grade 12 LIFE SCIENCES Paper 2 study notes was compiled by using at 2019 – 2021 DBE/ SACAI previous examination papers. The notes are compact, colourful and easy to study – giving possible answers directly from the memorandums. Making it perfect for learners with learning barriers or that strug...
Previous exam papers were used to compile these notes. SACAI SEP 2019 – 2021 & NOV 2019 – 2021.
These are just suggested answers from the memorandums. Some information is repeated, I want to
show you the different ways the same information is asked for.
I encourage you to answer the computation/illustration questions without even looking at the answers.
Good luck. Juffrou Ansie
TOPICS
1. DNA
2. MEIOSIS
3. GENETICS AND INHERITANCE
4. EVOLUTION THROUGH NATURAL SELECTION
5. HUMAN EVOLUTION
Multiple questions
“Out of Africa” hypothesis All humans originated from a common ancestor in Africa.
Mitochondrial DNA evidence showed that an African woman was the
ancestor of all humans.
,Gradualism Model for evolution suggested by Darwin that suggests that speciation
is slow and uniform.
DNA from fossils CANNOT be used as evidence for evolution
DNA-profiling/DNA The procedure used by forensic pathologists to identify criminals based
fingerprinting on the unique sequence of nucleotides on their DNA.
Africa The continent that is currently accepted as the cradle of humankind.
Lamarckism Acquired characteristics are inheritable.
RNA RNA is short single stranded. RNA differs from DNA in that it has uracil
and a ribose sugar.
Advantages of bipedalism • A person can see further to spot predators.
• It frees a person’s arms to carry things.
• It enables a person to cool down quicker.
Biotechnology/ Bio- The use of biological organisms or biological processes to make
engineering products that can improve human lives
Homologous structures Structures in different organisms that share similarities but have
different functions.
3:1 ‘A black furred rabbit is crossed with a white furred rabbit. All their
offspring (F1) is black. If two of their offspring is crossbred, their
offspring’s (F2) phenotypic ratio will be 3:1
BB x WW A black mouse was crossbred with a white mouse. All their offspring is
grey. The P1 genotype = BB x WW
Homo naledi This hominins are considered the most modern
Aneuploidy Down syndrome
XY Chromosomes of a boy
Gregor Mendel’s laws Law of independent assortment
The diagram illustrates part of a DNA molecule.
A single DNA nucleotide is shown by sub-unit(s): X, Y and Z together.
Type of inheritance is illustrated by the diagram below: Co-dominance
,Unstriped body with normal The alleles for striped body and normal antennae are dominant over
antennae the alleles for unstriped body and abnormal antennae. The phenotype
of the fly numbered 4 will be unstriped body with normal antennae.
The diagram illustrates a genetically engineered bacterial cell. The
structure labelled X is a plasmid.
Interphase The phase of the cell cycle during which DNA replication takes place.
Locus The specific position of each gene on a chromosome.
Ribosome The site of protein synthesis.
Chiasmata Points on a chromosome where crossing over takes place
Haploid A single set of chromosomes in a cell.
Anti-codons The triplet of three consecutive bases on t-RNA.
Monohybrid A genetic cross where only one hereditary characteristic is investigated
at a time.
Homozygous An individual that has two of the same alleles of a gene/ Having two
identical genes at the same locus.
Punctuated equilibrium Evolution occurs in sudden bursts after long periods of no change.
Alleles determine characteristics such as petal colour in flowers. An
allele is an alternative form of a gene.
Goltz Syndrome Goltz Syndrome is a condition in humans that adversely affects the skin.
It is inherited as a dominant gene carried on the X chromosome.
Layer 4 the of rock in the diagram below is most likely to contain the
oldest fossils
Statements is correct:
The domestic dog is closer related to the African wild dog than to the
jackal.
Biogeography The study of the distribution of species.
, Foramen magnum The opening in the skull through which the spinal cord leaves the brain.
Dr Lee Berger The South African palaeontologist who discovered Australopithecus
sediba.
Outbreeding Reproduction between unrelated members of a population.
Quadrupedalism The mode of walking permanently on four legs.
Cradle of Humankind The World Heritage Site in South Africa that is made up of thirteen
hominid fossil sites and over 200 caves.
Co-dominance Condition in which the two alleles of a gene have equal expression in
the phenotype of an organism.
Double helix The shape of a DNA molecule.
Genome All the genetic information of a species.
Evidence to support Homologous structures of a whale’s flipper and a bird’s wing
common ancestry
Metaphase Metaphase is a stage during the process of cell division (mitosis or
meiosis).
Mitosis Mitosis is the process by which body cells divide and create copies of
themselves for growth and repair.
Meiosis In meiosis, the new cells have half the genetic material of the parent
cell and is the process by which egg and sperm cells are formed.
Monohybrid crossing A genetic cross involving one characteristic controlled by a pair of
alleles
Homologous Having the same or a similar relation; corresponding, as in relative
position or structure. corresponding in structure and in origin, but not
necessarily in function: The wing of a bird and the foreleg of a horse are
homologous.
Homologous pairs Pairs of chromosomes, one from each parent, that carry the same
genetic information.
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