science yr 10 end of yr exam - complete

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)

base example

NaOH (sodium hydroxide)

test for gases

(hold a match over a reaction)
pop = hydrogen
flame go out = carbon dioxide
flame enlarge = oxygen

Ammonia

NH3

Octane

a type of hydrocarbon commonly used as fuel

Allotropes

Different forms of the same element (e.g. carbon = diamond = graphite)

collision theory

for a reaction to occur two particles must collide with sufficient speed/energy at the correct orientation

how does temp change rate of reaction

increasing the temperature increases the amount of energy in the reaction and therefore creates more frequent successful collisions and therefore increases the rate of reaction

what is the 10° rule?

for every 10° that the temperature increases, the rate of reaction doubles

what effect does concentration have on rate of reaction

it increases the number of particles moving around in the same volume resulting in more frequent successful collisions

what effect does surface area have on rate of reaction

gives more area to collide with the particles and therefore increases the amount of collisions that can occur e.g. sugar cube

what effect does adding a catalyst have on the rate of reaction

Adding a catalyst speeds up the rate of reaction

evolution

the change in a species' traits over time that allows it to survive

how did charles darwin develop his theory of evolution

he was working on the HMS Beagle, mapping the coast of south america. in the galapagos islands he saw variations in the finches off each island to suit the environments of each island (e.g. food type=larger beak)

what book did charles darwin write

on the origin of species by means of natural selection

what was lamarck's theory of evolution?

he believed that organisms would develop traits within their lifetime as an adaptation to the environment that would pass on to the next generation

what was darwin's theory of how evolution came to be

- organisms would be born with advantageous traits due to mutations
- animals with advantageous traits lived longer and therefore bred creating more of these species
- this throughout generations created species-wide change because of SURVIVAL OF THE FITTEST