Nitrogen bases: Adenine pairs with Thymine Guanine pairs with cytosine. Human male chromosome s. DNA is a double helix Genetic instructions are in the form of a code made up of 4 bases. DNA with bases. Inheritance- Parents who are both carriers of the Cystic fibrosis allele (c).
Adenine pairs with Thymine
Guanine pairs with cytosine
Human male chromosomes
DNA is a double helix
Genetic instructions are in the
form of a code made up of 4 bases
DNA with bases
Inheritance- Parents who are both carriers of the Cystic fibrosis allele (c).
Parents Cc x Cc
Gametes C or c x C or c
(egg/sperm) C c
Possible Outcomes C
75% Normal c
B1 You and Your Genes
Lobed ears are dominant over ears with no lobes
Cytoplasm: chemical reactions take place
Cell membrane: Controls movement into and out of the cell
Nucleus: contains genetic information
Mitochondria: Respiration takes place providing energy
Caused by recessive allele (so two copies of allele are needed).
A thick sticky mucus is produced affecting air passages and digestive systems
Each gene codes for
a particular protein
To determine any faulty alleles being passed on
Caused by dominant allele (one copy of allele are needed).
Loss of memory and neurone damage in the brain
Used to screen embryos for faulty alleles
Variation – caused by dominant/recessive alleles and environment
Stem cells - cells with no specific function. Can be turned into any cell
Arteries transport blood away from the heart
Veins transport blood into the heart
Capillaries exchange materials with tissues
Vasoconstriction and Vasodilation
Step 2: The cell produces antibodies
to “fit” the pathogen
Monitored by thermoregulatory centre in brain and receptors in skin.
-hair lies flat
-blood vessels dilate so heat lost through skin
-Goosebumps & hairs trap air
-blood vessels constrict
-shiver, respiration releases heat
B2 Keeping Healthy
Step 1: The lymphocyte “sees” the pathogen (microbe)
Step 4: The pathogens are “eaten” by the white blood cells
Step 3: The antibodies fit onto the pathogens and cause them to “clump”
Resistant Bacteria's – these are bacteria's that have mutated and antibiotics no longer are able to kill them.
Vaccines – dead or live proteins injected into the body. The body will make antibodies for the antigens of the microbes.
Risk Factor – when you increase the risk of getting the disease by doing the factor i.e. drinking alcohol
A factor that can cause an outcome. Correlation means that there is a common link between a factor and outcome.
Water Homeostasis – controlled by negative feedback of ADH.
What evidence is there that evolution is happening?
D______ proposed the theory of e______ to explain how species change over time. There is v_______ between individuals, those that are better a_______ are more likely to s________ and r________, passing on favorable characteristics.
Ocean, dessert, grass land,
Farm land, Aquarium, green house
The up and down pattern of predator and prey
population is called cyclic fluctuations
Believed that acquired characteristics can be inherited
Photosynthesis happens only during day but
respiration happens both during day and night
B3 Life on Earth
The presence or absence of an indicator species is
used to estimate levels of pollution Example: Lichens
Adaptation: features which help a plant
or animal survive in an extreme
environment,. Example: Polar bear, Camel and cactus
is taking things from the
environment but leaving
enough behind to
ensure a supply for
the future and
MUTUALISM: When both
Organisms benefit, example:
Pea plant and
nitrogen – fixing bacteria
“Species” means “a group of similar organisms” which are capable of interbreeding to produce fertile offspring, e.g. dogs
Hybrids are the result of breeding two
animals form different species, they
cannot reproduce and are sterile.
Example: Tiger +Lion = Tigon
Interspecific Competition – between two different species
Intraspecific Competition – between the same species
Origin of Species
Nitrogen & Carbon Cycle – how these elements form a cycle, uses of decomposition, respiration, consumption and photosynthesis
Biodiversity – different species living in the same habitat/ecosystem.