B5.1-Inheritance Flashcards
(37 cards)
What is a recessive allele?
An allele that is only expressed if you have two copies of the allele, one from each parent
What are the advantages and disadvantages of asexual reproduction ?
Advantages: if an offspring is well adapted to the area it will share an identical set of characteristics It is faster since only one parent is needed Disadvantages: changes to biotic and abiotic factors may result in the whole species dying out
Are all mutations harmful?
Not all mutations are harmful some mutations are neutral (neither benefit nor harm the organisms) Some can even be beneficial as conjugation in bacteria allows for antibiotics in plasmids to be transferred between cells
What is the second stage of meiosis?
- The chromosomes line up along the middle of each of the new cell 7. This time each chromosome is pulled in half. A single copy of each pair is pulled to opposite ends of the cell 8. The cell then divides into two. This results in four haploid cells that are genertically different
What is asexual reproduction?
Asexual reproduction is when an organism reproduces itself without a mate. This produces a clone with the exact genetic makeup of the parent
What is a gamete?
A gamete is a sex cell produced during sexual intercourse. It is a haploid cell since two gametes fuse to form a zygote (diploid cell).Examples are sperm and egg cells
How many pairs of chromosomes does a human have?
A human has 23 pairs of chromosomes. 22 pairs are identical in appearance. The 23rd pair known as the sex chromosomes are different. Two X chromosomes makes a girl and an X and a Y chromosome makes a boy.
What is sexual reproduction?
Sexual reproduction requires two parents. The offspring is not a clone since it is made from two sets of genes. This causes variation
What is the genotype?
Genotype is the genetic make up of an organism
What is the phenotype?
Phenotype is the physical characteristics of an organism e.g. hair colour, eye colour and skin colour
How can someone be heterozygous?
If someone has two different alleles
What do mutations affect?
Mutation affects an organisms genotype and rarely affects phenotype
How can a mutation affect phenotype?
If a mutation occurs within a gene dna bases may be changed or deleted. This changes the reading of the triplets so coding for different amino acids which code for different proteins and so affecting the phenotype
What is a haploid cell?
Cells that have 23 chromosomes (or D). They are produced in meosis.
What causes variation?
A group of genes controlling a certain variation
What are some examples of dominant characteristics?
Dark wavy hair, brown eyes, free ear lobes, freckles and a straight nose
What is a dominant allele?
A dominant allele is an allele that expresses itself even if you get it from one or both parents
What are examples of plants that can reproduce asexually?
Potato plants, spider plants and daffodils
How can you predict the outcome of a genetic cross?
By stating the phenotype ant genotype if the parents and making a punnet square diagram
Why is there a roughly the same amount of boys and girls in a population?
Because there is a 50% chance of conceiving a boy and a 50% chance of conceiving a girl
What are examples of recessive characteristics?
Straight blonde hair, blue eyes, no freckles, joined ear lobes and upturned nose
What is a genetic variant?
A genetic variant is a different version of an allele, which is caused by a change in the DNA. All variants occur from mutation
What is environmental variation?
Variation caused by the environment you live in
Are most mutations harmful?
Most mutations are harmful; They can cause cancer (cells divide uncontrollably) They can cause the production of abnormal protein channels (channels that allow molecules to be transported through the cell membrane) that do not function properly e.g cystic fibrosis
