B6 - Inheritance, Variation & Evolution Flashcards
What does DNA stand for?
DeoxyriboNucleic Acid
What type of molecule is DNA
Polymer
Where is DNA found in a cell?
Nucleus
What is a gene?
A gene is a short section of DNA
What is the definition for genome?
The entire genetic material in an organism
What are the repeating units called in DNA polymers?
Nucleotides
What 3 things does each nucleotide contain?
- 1 sugar group
- 1 phosphate group
- 1 ‘base’
What do the sugar and phosphate groups form?
Backbone to the DNA
What are the names of the 4 bases?
A, T, G, C
What are the base pairings?
A and T, G and C
How many bases does each amino acid get coded by?
3
Where are proteins made in a cell?
Ribosomes
What does mRNA stand for?
messenger RiboNucleic Acid
What does mRNA do?
Transfers genetic code from DNA to the ribosomes
Name 3 examples of types of proteins
1) Enzymes
2) Hormones
3) Structural proteins
What happens to a chain of amino acids once it’s been assembled?
It folds into a unique shape, allowing the protein to do its designated task
What are the 3 different ways that mutations can change a DNA base sequence?
1) Insertions - where a new base is inserted into the DNA base sequence where it shouldn’t be
2) Deletions - when a random base is deleted from a base sequence
3) Substitutions - when a random base in the DNA base sequence is changed to a different base
What is sexual reproduction?
Where genetic information from 2 organisms (mum and dad) is combined to produce offspring which are genetically different to either parent
In sexual reproduction, the mum and dad produce gametes by what process?
Meiosis
In humans, how many chromosomes are in each gamete?
23
How many parents are there in asexual reproduction?
1
What process does asexual reproduction happen by?
Mitosis
What is a mutation?
A random change in an organism’s DNA
What do mutations do?
They change the sequence of the DNA bases in a gene, which produces a genetic variant
Explain the process of meiosis
1) The genetic information is duplicated. After this, the chromosomes begin to arrange themselves into pairs
2) In the first division of meiosis the chromosome pairs line up in the centre of the cell
3) The pairs are then pulled apart so each new cell only has one copy of each chromosome. Some of the father’s and mother’s go into each new cell
4) In the second division, the chromosomes line up again in the centre if the cell. The arms of the chromosome are pulled apart
5) You get 4 gametes, each with only a single set of chromosomes in it. Each of the gametes is genetically different from the others because the chromosomes all get shuffled up during meiosis and each gamete only gets half of them, at random
What do the 2 gametes do after they’ve fertilised?
The resulting new cell divides by mitosis to copy itself
What are some advantages of sexual reproduction over asexual reproduction?
- The organism inherits genes from both parents, which produces variation in the offspring
- Variation increases the chance of a species surviving a change in the environment
- Because adapted species have a better chance of survival, they’re more likely to breed successfully and pass the genes for characteristics on
- We can use selective breeding to speed up natural selection, allowing us to produce animals with desirable characteristics
What are some advantages of asexual reproduction over sexual reproduction?
- Only one parent is needed
- Uses less energy
- Faster
- Many identical offspring can be produced in favourable conditions
How is a parasite transferred to a human by a mosquito?
When the parasite bites the human is when the parasite is transferred
When does a parasite reproduce sexually and asexually?
- Sexually - when the parasite is in the mosquito
- Asexually - when the parasite is in the human
How do fungi reproduce?
They release spores, which can become new fungi when they land in a suitable place
What are ‘runners’ on strawberry plants?
- ‘Runners’ are stems which grow horizontally on the surface of the soil away from a plant
- At various points along the runner, a new strawberry plant forms that is identical to the original plant
How many of the 22 pairs of chromosomes are matched pairs that only control characteristics?
22
Which pair of chromosomes are label XX or XY?
23rd pair
Which chromosomes do males have?
XX
Which chromosomes do females have?
XY
How do you find the probability of getting a boy or a girl?
Draw a genetic diagram
Why does genetic variation within the malarial parasite population increases whilst in the mosquito?
The malarial parasite secually reproduces whilst in the mosquito, which leads to genetic variation
