genetics
the study of how traits are passed down from parent to offspring
traits
characteristics that a person has, can be hereditary
nature vs nurture
the concept of whether a trait occurred due to an organism's genetics or upbringing/environment
inherited characteristics (w/ examples)
traits that are genetic and inherited from an offspring's parents e.g. eye colour, blood type, curly hair
acquired traits (w/ examples)
traits obtained from the environment that are NOT hereditary e.g. scar, tattoos
deoxyribonucleic acid (DNA)
A long thin molecule that makes up part of a chromosome, in double helix shape
where is DNA contained in a cell
inside chromosomes in the nucleus
polymer structure
the structure of DNA in which it is made up by many small, repeating molecular units
DNA molecular unit
nucleotide
how many chromosomes are in each cell?
46 in 23 pairs
parts of a nucleotide
deoxyribose (sugar), phosphate and a nitrogenous base
the 4 types of nitrogenous bases
Adenine (A), Thymine (T), Cytosine (C), Guanine (G)
nitrogenous base pairs
A + T , C + G, held together by hydrogen bonds
mitosis
cell division in which the nucleus divides into 2 identical nuclei
why is mitosis important?
for growth and repair of the body
meiosis
cell division that produces reproductive cells (gametes) in sexually reproducing organisms and caues variation
where does meiosis occur?
only in reproductive cells; sperm or egg
how does meiosis create variation?
23 of the father's chromosomes and 23 of the mother's chromosomes combine during fertilisation to create a full set of 46 chromosomes, in this process the genes are shuffled and create variation meaning a parent never looks identical to their offspring.
heterozygous
having two different alleles
homozygous
having two identical alleles
how is the probability of inheriting certain genes represented?
punnet square with capital letter for dominant and lowercase for recessive
dominant gene
gene that produces the same phenotype in the organism whether or not its allele identical
recessive gene
gene that produces its characteristic phenotype only when its allele is identical
allele
different forms of the same gene e.g. blue eyes and brown eyes BOTH EYE COLOUR GENES
if both parents are heterozygous ( have the A and a gene), what is the probability the offspring receives the recessive gene?
25%
mutation
an alteration in the inherited nucleic acid sequence of the genotype of an organism, can create variation
point mutation
a mutation due to a change in the nitrogenous bases in one or more of the
types of point mutation
Substitution → the wrong base is matched
Insertion → extra base/s are added in
Deletion → base/s are removed
dangers of point mutation
especially in deletion and insertion, the entire DNA sequence can be altered because DNA is read in 3s
chromosomal mutations
mutation caused by harmful chemicals, radiation or random chance, causing a rearrangement of the chromosomes already present
types of chromosomal mutation
Duplication →extra copies of genes are generated
Deletion → some genetic material breaks off
Inversion → when a broken chromosome segment gets inversed (reversed) and put back on the chromosome
Translocation → when a fragment of DNA breaks off and adds onto another chromosome
label male reproductive system
https://www.proprofs.com/quiz-school/playquiz/?title=reproductive-system--human-male
label female reproductive system
http://www.kscience.co.uk/revision/reproduction/female/femalelabel.htm
role of the testes in reproduction
produce sperm and hormones for reproduction and bodily development
testosterone
essential male hormone for development and sperm production
role of the ovaries
produce eggs to be fertilised into zygotes and produce progesterone and Oestrogen
oestrogen
female hormone for maintenance of reproductive system
progesterone
hormone that prepares the uterus for pregnancy and lactation
cloning
when an organism is a direct biological copy of its parent
phenotype
an organisms physical/visible genes (i.e. the genes applied not carried, e.g. brown-haired person's phenotype is brown but may carry the blond allele)
asexual reproduction
reproduction without the fusion of gametes, with only one parent
karyotype
an organism's set of chromosomes
haploid
an organism or cell having only one complete set of chromosomes
genetic engineering
technology of altering DNA codes of living organisms
examples of genetic engineering
selective breeding, CRISPR technology, recombinant bacteria
how can recombinant bacteria be used?
create recombinant bacteria with the desired trait, insert into organism and allow bacteria to 'infect', results in desired trait. can be used to create growth hormones and human insulin
Do metals lose or gain electrons?
lose electrons
Do nonmetals gain or lose electrons?
gain
what does a chemical reaction always involve?
an energy change
Law of Conservation of Energy
Energy cannot be created or destroyed
Law of Conservation of Mass
Matter is neither created nor destroyed
in chemical reactions, atoms don't disappear or appear they...
rearrange themselves
Exothermic
Chemical Reaction in which energy is released in the form of heat. Feel hot
Exothermic example
lighting a match
Endothermic
a chemical reaction that absorbs heat energy- feels cold
endothermic example
instant icepacks
Combustion
when a substance reacts quickly with oxygen to release heat and light energy
Is combustion endo or exothermic?
exothermic
Hydrocarbons
compounds that are used as fuels and are combusted- react with large amounts of oxygen
corrosion
the deterioration of a metal due to a chemical reaction in the environment
corrosion formula
metal + oxygen -> metal oxide
how are corrosion and combustion similar?
both require oxygen but they occur at different speeds
Is corrosion endothermic or exothermic?
exothermic
decomposition reaction
a reaction in which a single compound breaks down to form two or more simpler substances. ONE REACTANT
decomposition general equation
AB --> A + B
combination/composition reaction
a chemical change in which two or more substances react to form a single new substance
composition/combination reaction general equation
X + Y --> XY
precipitation reaction
A reaction in which a solid, insoluble product forms upon mixing two solutions.
precipitate
A solid that forms from a solution during a chemical reaction.
precipitation general equation
AB (aq) + CD (aq) = AD (s) + CB (aq)
polyatomic ion
an ion made of two or more atoms (that exists as a package)
Isotope
Atoms of the same element that have different numbers of neutrons
Respiration
The process by which cells break down simple food molecules to release the energy they contain.
Where does respiration occur?
mitochondria
Respiration formula
C6H12O6 + 6O2 --> 6CO2 + 6H2O + energy
Respiration word formula
Glucose + oxygen --> carbon dioxide + water + ATP (energy)
Photosynthesis
Plants use the sun's energy to convert water and carbon dioxide into sugars
Where does photosynthesis occur?
Chloroplast
Photosynthesis formula
carbon dioxide+ water + sunlight ---> glucose + oxygen
Neutralisation reaction
acid + base = salt + water
Acid + Carbonate
acid + carbonate = salt + water + carbon dioxide
Acid + Metal
acid + metal = salt + hydrogen gas
Carbonate example
CaCO3 (calcite)
Acid example
HCl (hydrochloric acid)
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