Inheritance/Mendel
Variation
DNA
Meiosis/Mitosis
Vocab
100
What is variation
Differences between individuals of the same species
100
What is variation?
Differences between individuals of the same species
100
What are the parts of a nucleotide? Name all the options for bases and their paring.
Base, Phosphate, Sugar - Guanine with Cytosine and Adenine with Thymine.
100
What is the difference between meiosis and mitosis?
One creates a new cell with 23 pairs of chromosomes the other creates a cell with 23 chromosomes.
100
These pairs of chromosomes code for the same characteristics
What is Homozygous?
200
Heterozygous individual that has a recessive allele that is not expressed
What is a Carrier?
200
Ear piercing, tattoos, hair coloring are examples of what?
Non-inherited variation
200
DNA stands for what? (Correct spelling) What shape is it described as?
Deoxyribonucleic acid, double helix.
200
A somatic cell is what?
Any cell in the body that has 23 pairs of chromosomes - cheek cells and muscle cells.
200
These pairs of chromosomes code for the same characteristics
What is an Allele?
300
If the both parents are heterozygous for a trait what is the genotypic offspring ratio?
BB = 25%, Bb = 50%, bb = 25%
300
What are the disadvantages of asexual reproduction?
Lack of variation means that they can all be killed by the same pest, disease or change in weather.
300
A section of DNA codes for what?
A gene?
300
What is the difference between an haploid and a diploid cell?
The number of chromosomes - haploid has 23 chromosomes. Diploid cells have 46.
300
The two alleles available in an individual
What is a Genotype?
400
What does a test cross enable you to find out? How?
is used to determine if an individual exhibiting a dominant trait is homozygous or heterozygous for that trait. More simply test crosses determine the genotype of an individual with a dominant phenotype. Test crosses involve breeding the individual in question with another individual that expresses a recessive version of the same trait. If all offspring display the dominant phenotype, the individual in question is homozygous dominant; if the offspring display both dominant and recessive phenotypes, then the individual is heterozygous.
400
Some animals produce asexually then reproduce sexually. Why is this advantageous?
Dispersal is the initial phase. Clones are dispersed, grow then reproduce sexually. When they reproduce sexually there is often more genetic variation in their new area. This allows for higher variation in the species.
400
What happens to the number of chromosomes during meiosis, why?
The number is halved because the cells created become haploid so that they can be joined with a gamete from the other parent to create a diploid cell.
400
Describe the process of mitosis. - Detail
Each chromosome ‘unzips’, forming identical chromatids held together at one point. The chromosomes move to the ‘equator’ of the cell and spindle fibres attach to each chromatid. The spindle fibres pull the chromatids to opposite poles. The cell divides and nuclear membranes form around each group of chromosomes.
400
The scientific word for a characteristic we inherit from our parents
What is Trait?
500
In a pedigree chart if the offspring have the recessive trait describe the genotypes of the parents.
Both must be carriers. They can either be homozygous recessive or heterozygous. If one parent is homozygous dominant there is no chance that the offspring has the recessive allele.
500
How does meiosis support genetic variation?
Crossing over is a stage in meiosis that creates variation within the organism then the haploid gametes join with other gametes which creates more variation.
500
How is DNA profiling able to help identify suspected criminals? Go into detail.
Because it identifies the DNA fingerprint of individuals. This fingerprint is identical for everyone except identical twins. Variation is created because of the extent that DNA can be manipulated.
500
Describe the process of meiosis. - Detail
The chromosomes become visible when they shorten and thicken, like a compressed spring. They replicate, forming identical chromatids. Crossing over occurs when homologous chromosomes pair up and twist round each other. Chunks of genes are exchanged, creating a unique mix of genes on each chromosome. Chromosomes line up in pairs, then move to separate poles in the first cell division. A second cell division occurs, separating the chromatids. The result is four cells, each with the haploid number of chromosomes.
500
A cross that determines if an individual is heterozygous or homozygous?
What is a Test Cross?
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