April Test 3 Flashcards
What does evolution mean?
A gradual change in the characteristics of a species over time
Why is it hard to find evidence of evolution?
Because some is destroyed by earthquakes
How is the age of a stone tool worked out?
By looking at the rock it’s made with
What is genetic variation?
The characteristics of individuals vary in a population due to gene difference
What is natural selection?
By chance some individuals have variations that make them better at coping and more likely to survive
What is inheritance?
Naturally selected survivors breed and pass on their variations to offspring
What’s the best way to remember the classification of an animal?
Kings Play Chess On Fire Grain Sand
Kingdom Phylum Class Order Family Genus Species
What do plants have that animals don’t?
Chloroplasts
Definition of species?
A group of similar organisms capable of reproducing
Definition of breed?
Members of an animal species differing from others slightly
Definition of variety?
Members of a plant species differing from others only slightly
What is artificial selection?
When humans breed organisms with useful characteristics to create new breeds/varieties with desired characteristics
Problems with selective breeding?
Takes a long time for desired characteristics
Large numbers may be disease prone
Concerns over animal welfare
What is a calorimetry?
The dry food flame experiment
What is diffusion?
Movement of particles from a high concentration to a low concentration
What is osmosis?
The net movement of water molecules across a partially permeable membrane from a high concentration to a low one
What is active transport?
The movement of particles across a membrane across a concentration gradient
Two differences between diffusion and active transport?
Active transport requires energy
In active transport particles are moved UP a concentration gradient not DOWN
What is a chromosome?
A coiled up length of DNA molecules
How do you calculate the number of cells produced by mitosis?
2^n
n=number of divisions
How is cancer caused?
When a cell starts dividing uncontrollably due to a change in one gene, causing a tumour
What is a stem cell?
An undifferentiated cell
Where are stem cells found?
In embryos
Risks of stem cells?
They divide very quickly
They may carry disease
The body may reject them
How does a reflex happen?
- Touch flame
- Receptor
- Sensory
- Synapse
- Relay
- Synapse
- Motor
- Effector
Why is alcohol added to DNA?
To get the DNA out as it isn’t soluble in alcohol
What decides the order of amino acids in a protein?
The order of the bases
Instead of T what does mRNA use?
U
Transcription
- RNA polymerase binds to a region of DNA in front of a gene
- The two DNA strands unzip
- The RNA polymerase uses the coding DNA as a template to make mRNA
- The mRNA leaves the nucleus and joins with a ribosome
Translation
- tRNA brings amino acids to the ribosome
- Codon and anticodon make sure amino acids are in the right order
- Amino acids join together and a polypeptide is made
Which chromosome pair determines gender?
23rd
Genotype
The combination of alleles you have
What is the human genome project?
Researchers mapped 20,500 genes
Drawbacks of genome mapping?
Increased stress if you know you’re susceptible
Discrimination by employers and insurance
People under pressure not to have children
The deeper the rock the…
Older the fossil
Who came up with the theory of evolution? Who also contributed?
Charles Darwin
Wallace
What did Wallace come up with?
Natural selection theory
Butterflies had warning colours on wings to deter predators
How old is Ardi? Key characteristics?
4.4 million years old
Feet to climb trees
Long arms and short legs
Chimp like brain size
How old is Lucy? Key characteristics?
3.2 million years old
Feet more adapted to walking
Arms and legs more human like
Larger brain
How old is Turkana Boy? Key characteristics?
1.6 million years old
Short arms long legs
Bigger brain again
Order these
Homo habilis
Homo sapien
Homo neanderthalis
Homo erectus
Habilis
Erectus
Neanderthalis
Sapiens
Pentadactyl limb
Limb with 5 digits
What are the 5 kingdoms?
Animals Plants Fungi Prokaryotes Protists
Process of selective breeding?
Select the animals/plants with the desired characteristics and breed them
Select the best offspring and breed them
Continue this over several generations
Process of tissue culture?
Take tissue from plant
Grow tissue in medium containing growth hormones
Move to potting compost to carry on growing
How does genetic engineering work?
DNA is cut out with enzyme, vector DNA is then cut OPEN with same enzyme
They are mixed together with ligase enzymes
The result is recombinant DNA which is inserted into bacteria for example
What can GMOs be used for?
Provide more food for people insect resistance in crops
