B11 - Inheritance Flashcards
Define inheritance.
the transmission of genetic information from generation to generation.
Define chromosome.
a thread-like structure of DNA, carrying genetic information in the form of genes.
Define gene.
a length of DNA that codes for a protein.
Define allele.
a version of a gene.
Define haploid nucleus.
a nucleus containing a single set of unpaired chromosomes.
Define diploid nucleus.
a nucleus containing two sets of chromosomes.
Define mitosis.
nuclear division giving rise to genetically identical cells.
Define meiosis.
reduction division in which the chromosome number is halved from diploid to haploid resulting in genetically different cells.
Define genotype.
the genetic make-up of an organism in terms of the alleles present.
Define phenotype.
the observable features of an organism.
Define homozygous.
having two identical alleles of a particular gene.
Define heterozygous.
having two different alleles of a particular gene.
Define dominant.
an allele that is expressed if it is present.
Define recessive.
an allele that is only expressed when there is no dominant allele of the gene present.
Define variation.
differences between individuals of the same species.
Define mutation.
a change in a gene or chromosome.
What are examples of cells with haploid nuclei?
gametes / sperm / egg / pollen / ovule
What are examples of cells with diploid nuclei?
all body cells
How many pairs of chromosomes are in human diploid cells?
23
What is the 23rd pair of chromosomes called?
the sex chromosome
What is the chromosome pair for males and females?
male - XY
female - XX
Where is DNA found?
the nucleus of cells.
What is made of DNA?
genes.
Why is DNA essential for life?
genes determine all our features and cell activity.
