Inheritance, Variation & Evolution Flashcards
What is the main difference between meiosis and mitosis?
Meiosis leads to non-identical cells being formed while mitosis leads to identical cells being formed.
What are the male and female gametes in animals?
Sperm and egg cells.
What is the result of sexual reproduction?
Mixing of genetic information which leads to variety in the offspring.
What type of reproduction involves only one parent?
Asexual reproduction.
What are the advantages of sexual reproduction?
- Produces variation in the offspring
- Variation gives a survival advantage by natural selection
- Natural selection can be speeded up by humans in selective breeding
What are the advantages of asexual reproduction?
- Only one parent needed
- More time and energy efficient
- Faster than sexual reproduction
- Many identical offspring can be produced
What is the role of meiosis in gamete formation?
Meiosis halves the number of chromosomes in gametes.
What happens during fertilization?
Gametes join to restore the normal number of chromosomes.
What is the genetic material in the nucleus of a cell?
DNA.
What is a gene?
A small section of DNA on a chromosome that codes for a particular sequence of amino acids.
What is the entire genetic material of an organism called?
Genome.
What is the Human Genome Project?
A project that studied the entire human genome to improve understanding of genes linked with diseases.
What are the four bases of DNA?
A, C, G, and T.
What is the function of ribosomes in protein synthesis?
Ribosomes synthesize proteins according to a template.
What is a mutation?
A change in the DNA sequence that can affect the protein produced.
What is a dominant allele?
An allele that is always expressed, even if only one copy is present.
What is a recessive allele?
An allele that is only expressed if two copies are present.
What does homozygous mean?
Having two identical copies of alleles for a particular trait.
What does heterozygous mean?
Having two different forms of a gene (alleles) for a particular trait.
What is polygenic inheritance?
A characteristic that is controlled by multiple genes.
What is the process of selective breeding?
Selecting individuals with desirable characteristics and breeding them together.
What is genetic engineering?
The process of modifying the genome of an organism by introducing a gene from another organism.
What are genetically modified (GM) crops?
Crops that have had their genes modified to exhibit desired characteristics.
What is embryo screening?
Analyzing genes of an embryo to detect genetic disorders.
What are the sex chromosomes in males and females?
Females have XX and males have XY.
What is variation in a population?
Differences in the characteristics of individuals due to genetic and environmental causes.
What are some examples of genetic variation in humans?
- Blood group
- Eye colour
- Gender
- Ability to roll tongue
- Free or fixed earlobes
What is evolution?
A change in the inherited characteristics of a population over time through natural selection.
What is the impact of selective breeding on agriculture?
Increases yields and quality of plant and animal products.
What are crops that have had their genes modified called?
Genetically modified (GM) crops
What is one concern about GM crops?
Effects on populations of wild flowers and insects
What is a potential health concern related to GM crops?
Effects on human health have not been fully explored
What is the role of enzymes in genetic engineering?
Used to isolate (cut out) the required gene
What is a vector in genetic engineering?
Usually a bacterial plasmid or a virus used to insert a gene into target cells
What is tissue culture?
Using small groups of cells from part of a plant to grow identical new plants
What are cuttings in plant propagation?
A method used to produce many identical new plants from a parent plant
What occurs during adult cell cloning?
The nucleus from an adult body cell is inserted into an unfertilised egg cell
Who proposed the theory of evolution by natural selection?
Charles Darwin
What is a key component of Darwin’s theory of evolution?
Individual organisms show a wide range of variation
What must individuals with advantageous characteristics do?
Survive to breed successfully
When was Darwin’s ‘On the Origin of Species’ published?
1859
What was a reason for the gradual acceptance of Darwin’s theory?
It challenged the idea that God made all animals and plants
Who independently proposed the theory of evolution by natural selection alongside Darwin?
Alfred Russel Wallace
What is Gregor Mendel known for?
Carrying out breeding experiments on plants
What are ‘units’ in Mendel’s experiments now known as?
Genes
What significant structure was determined in the mid-20th Century?
The structure of DNA
What is a clear piece of evidence for evolution?
Antibiotic resistance in bacteria
What is an antibiotic?
A chemical that can kill or inhibit the growth of bacteria
What happens to resistant bacteria when an antibiotic is used?
They survive and reproduce with less competition
What are some factors that can lead to extinction?
- New diseases
- New predators
- Environmental changes
- Catastrophic events
What is MRSA?
A strain of bacteria resistant to antibiotics
What should doctors avoid to reduce antibiotic resistance?
Prescribing antibiotics inappropriately
Who developed the classification system for living things?
Carl Linnaeus
What are the three domains in the three-domain system?
- Archaea
- Bacteria
- Eukaryota
What do evolutionary trees represent?
How scientists believe organisms are related
What is the significance of DNA sequencing in classification?
Shows relatedness of species based on base sequence similarity
What does the term morphology refer to?
The overall form and shape of an organism
What is the role of fossils in understanding evolution?
They provide evidence of how organisms have changed over time
What can lead to rapid evolution in bacteria?
Fast reproduction rates
What is the primary method of genetic modification in plants?
Tissue culture
Fill in the blank: The mechanism of inheritance and variation was not known until _______.
50 years after the theory was published
What are the reasons for embryo screening?
Can avoid suffering by stopping children from being born with genetic disorders.
Treatments for disorders cost a lot of money, money which will have to be payed by tax payers.
Laws in place to stop embryo screening abuse.
What are the reasons against embryo screening?
Process could imply that people with genetic disorders are undesirable which is not fair or true.
Very expensive and not available to all potential parents.
Could be abused by parents who choose exactly what characteristics they want their child to have.
