Gr 12 Life Sciences 2024 Paper 2
SACAI SEP 2019 – 2021 & NOV
2019 – 2021, NSS DBE/ November 2023, EC/SEPTEMBER 2023..
TOPICS
Multiple questions
1. DNA p. 8
2. GENETICS AND INHERITANCE p. 19
3. MEIOSIS p. 37
4. EVOLUTION THROUGH NATURAL SELECTION p. 36 - 53
& HUMAN EVOLUTION
Previous exam papers were used to compile these notes. SACAI SEP 2019 – 2021 & NOV
2019 – 2021, NSS DBE/ November 2023, EC/SEPTEMBER 2023.. 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
Multiple questions
1. DNA p. 8
2. GENETICS AND INHERITANCE p. 19
3. MEIOSIS p. 37
4. EVOLUTION THROUGH NATURAL SELECTION p. 36 - 53
& HUMAN EVOLUTION
@Juffrou_Ansie
, 2
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 fingerprinting The procedure used by forensic pathologists to identify
criminals based 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-engineering The use of biological organisms or biological processes to
make 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 These hominins are considered the most modern
Aneuploidy Down syndrome
XY Chromosomes of a boy
Gregor Mendel’s laws Law of independent assortment
@Juffrou_Ansie
, 3
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
antennae dominant over 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.
The process of DNA replication 1. The (DNA) double helix unwinds and – unzips
DBE/November 202 /hydrogen bonds break to form two separate strands
2. Both (DNA) strands serve as templates to build a
complementary (DNA) strand/ A pairs with T and C
pairs with G using free (DNA) nucleotides from the
nucleoplasm
3. This results is two identical (DNA) molecules
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.
@Juffrou_Ansie
, 4
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 of the 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.
@Juffrou_Ansie
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