Inheritance Flashcards
What is the genome?
The totality of genetic information in a cell or organism.
What does DNA stand for?
Deoxyribonucleic acid.
Where are chromosomes found?
In the nucleus of animal and plant cells.
What are genes?
Segments of DNA which code for specific proteins or regulators.
What shape do chromosomes take during mitosis?
A fuzzy X shape.
How many autosomal chromosomes do human male body cells have?
44 autosomal chromosomes.
What are the sex chromosomes for human females?
XX.
What is the chromosome number in human somatic cells?
46 (23 pairs of chromosomes).
What is the chromosome number in gametes?
Haploid (half the chromosome number).
What do sperm and eggs contain in terms of chromosomes?
Sperm: 22 autosomal + 1 sex chromosome (X or Y); Eggs: 22 autosomal + 1 sex chromosome (X).
Define haploid.
Cells with only one chromosome of each pair.
Define diploid.
Cells with two copies of each chromosome.
What occurs during mitosis?
One cell duplicates into two genetically identical daughter cells.
What is the purpose of meiosis?
Formation of gametes with half the number of chromosomes.
What is fertilisation?
The union of the nuclei of the female and male gametes to produce a zygote.
What determines genetic sex in humans?
Sex chromosomes (X and Y).
Define allele.
The variant or form of a gene.
What is the difference between genotype and phenotype?
Genotype: combination of alleles; Phenotype: observable characteristic.
What is dominant inheritance?
One allele is dominant and masks the effects of a recessive allele.
What is the expected probability of offspring genotypes using a Punnett square?
1 in 4 chance for homozygous dominant; 50% chance for heterozygous; 1 in 4 chance for homozygous recessive.
What is an autosomal dominant trait?
Affected individuals have at least one dominant allele.
What is an autosomal recessive trait?
Individuals are affected if they have both recessive alleles.
What are sex-linked genes?
Genetic characteristics where the alleles are located only on the X chromosome.
What is a gene mutation?
An alteration to the DNA base sequence of a gene.
