What is the genetic constitution of an organism called?
Genotype
Refers to the combination of alleles an organism possesses.
What term describes the observable characteristics of an organism resulting from gene expression and environmental interaction?
Phenotype
Includes traits such as height, eye colour or enzyme activity.
A gene may exist in several different forms within a population. What are these alternative forms called?
Alleles
Different alleles arise through mutation of the same gene locus.
True or False:
In diploid organisms, two identical alleles at a gene locus describe a homozygous condition.
True
Homozygous individuals carry two copies of the same allele.
True or False:
A heterozygous individual carries two identical alleles of a gene.
False
Heterozygous means two different alleles are present at a locus.
What type of allele is expressed in the phenotype even when only one copy is present?
Dominant
A dominant allele masks the effect of a recessive allele in heterozygotes.
What type of allele is only expressed in the phenotype when two copies are present?
Recessive
Recessive alleles are masked by dominant alleles in heterozygotes.
When two different alleles are both fully expressed in the phenotype, what pattern of inheritance is shown?
Codominance
Both alleles contribute equally to the phenotype (e.g., ABO blood group AB).
What type of genetic cross involves the inheritance of one gene with two alleles?
Monohybrid cross
Often produces a 3:1 phenotypic ratio when alleles show complete dominance.
What type of genetic cross examines inheritance of two different genes simultaneously?
Dihybrid cross
Independent assortment often produces a 9:3:3:1 phenotypic ratio.
Fill in the blank:
A statistical test used to compare observed phenotypic ratios with expected ratios in genetics is the ______-______ test.
Chi-squared
Used to determine whether deviations from expected ratios are due to chance.
True or False:
The chi-squared test can determine whether differences between expected and observed genetic ratios are statistically significant.
True
If the calculated value exceeds the critical value, the difference is significant.
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1: Biological Molecules138
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1: Enzymes & Digestion16
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1: Cell Structure52
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1: Cell Division20
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1: Membranes & Transport20
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2: Exchange & Transport Systems76
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2: Plant Transport20
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2: Immunology36
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3: DNA & Protein Synthesis27
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3: Genetic Diversity14
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3: Biodiversity & Classification32
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4: Evolution42
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