Inheritance, Variation and Evolution Flashcards
(16 cards)
What is meant by “double helix”?
A DNA molecule with the shape of a double-stranded spiral.
What do genes code for?
A particular sequence of amino acids which are put together to make a specific protein.
What is the name for the entire set of genetic material in an organism?
Genome
Name the male and female gametes in animals.
Sperm and egg cells
State the type of cell division used to make gametes in humans.
Meiosis
What is the probability that offspring will have the XX combination of sex chromosomes?
50%
Give two ways fossils can be formed.
From casting and impressions.
From gradual replacement of minerals.
From preservation in places where no decay happens.
What is the chance of a child being born with polydactyly if one parent has a single dominant allele for the gene that controls it?
50%
How might farmers use selective breeding?
To improve yields.
What leads to the formation of antibiotic-resistant strains of bacteria?
Random (rare) mutations in DNA cause bacteria cells to become resistant to antibiotics. As these cells multiply, more bacteria becomes resistant.
Name the groups that organisms are classified into the Linnean system.
Kingdom, phylum, class, order, family, genus, species.
Who proposed the “three-domain system” of classification in 1990?
Carl Woese
What is variation?
Differences within the same species.
Explain how beneficial characteristics become more common in a population over time.
Organisms with the most beneficial characteristics are more likely to survive than others and then reproduce, passing on their characteristics to the next generation. This is repeated over time.
What is genetic engineering?
Transferring a gene responsible for a desired characteristic from one organism’s genome into another organism, so that it has the desired characteristics.
Give two arguments for and two arguments against screening embryos for genetic disorders.
For - It helps to stop people suffering, treating disorders costs the government a lot of money.
Against - It implies that people with genetic problems are “undesirable” (could increase prejudice), screening is expensive.
