Inheritance — IGCSE Biology (0970) questions by topic

What are alternative forms of genes called? A alleles B chromosomes C genotypes D phenotypes

What is an alternative form of a gene called? A allele B chromosome C genotype D protein

Cystic fibrosis is an inherited condition that occurs when an individual is homozygous for the recessive allele. If both parents are heterozygous for this characteristic, what is…

The diagram shows the chromosomes in the nucleus of a cell that divides by mitosis. The parent nucleus contains a set of chromosomes. Which diagram shows the chromosomes in the…

A farmer bred together male cattle with white hair and female cattle with red hair. All the offspring produced had roan hair (a mixture of red and white). He then repeatedly bred…

Part of the base sequence of DNA from four species was determined. species 1 T C A G G A T T species 2 T G A G C A A T species 3 T G A G C A A G species 4 T G A G G A T T Which…

The diagram shows the inheritance of a genetic condition in one family. The pedigree chart uses a key: shaded circle = female with condition; unshaded circle = female without…

What describes an allele? A an alternative form of a chromosome made of DNA B an alternative form of a chromosome made of protein C an alternative form of a gene made of DNA D an…

The diagram shows the sticky end of the DNA of a plasmid that has been cut by a restriction enzyme. The unpaired bases are labelled C A G T G. What is the correct sequence of the…

The pedigree diagrams show the pattern of inheritance of a genetic disorder in four families (A–D). This genetic disorder is not sex-linked. Which pedigree diagram proves that the…

The diagram shows the bases in a section of DNA from one strand only: A−C−T−T−C−A−G−T−C. What is the base sequence on the complementary DNA strand? A G−C−T−T−C−G−A−T−C B…

In a family, the two parents have blood groups A and B and the three children have blood groups B, B and O. What are the genotypes of the parents? A IAIA and IBIB B IAIB and IAIo…

The melanin gene in humans codes for a pigment produced in the skin, hair and eyes. Describe what is meant by the term gene.

What do genes code for?

When white-flowered pea plants are crossed with red-flowered pea plants, the offspring plants all have red flowers. If these offspring plants are crossed, the next generation of…

Which base in a DNA molecule always pairs with a G base?

Why do different cells in a human body produce different proteins?

Which graph shows the mean mass of DNA per cell before, during and after mitosis? Graph A: starts at ~7 units, rises sharply, stays high, then returns to ~7 Graph B: starts at ~4…

Which statement about gene mutations is correct?

Fig. 5.1 is a pedigree diagram showing the inheritance of blood group in one family. Individual 1 (male, blood group B) and individual 2 (female, blood group A) are parents. Their…

What is defined as a length of DNA that codes for a protein? A amino acid B antibody C chromosome D gene

A man has three sons. What is the chance of his next child being a daughter? A 0% B 25% C 50% D 100%

Which human characteristics are inherited? The table considers blood group, eye colour, language and sex for rows A–D (key: shaded = inherited, blank = not inherited). A B C D

When breeding, which pair of parents will be pure-breeding for a particular characteristic? A a heterozygous and a homozygous individual B two heterozygous individuals C two…

In a pea plant, the allele for round seeds, R, is dominant to the allele for wrinkled seeds, r. If plants with the genotype Rr are crossed, what are the likely proportions of…

The structure of DNA involves two strands coiled together to form a double helix. Which pairing of bases between the two strands is correct? A A and G B A and T C C and A D C and T

The statements describe how a protein is made. 1 mRNA passes through a ribosome. 2 mRNA molecules carry a copy of the gene to the cytoplasm. 3 The gene coding for the protein is…

Which parents could produce offspring with blood group O? A heterozygous father with blood group A and heterozygous mother with blood group B B heterozygous father with blood…

The diagram shows the inheritance of albinism in one family (a pedigree). Albinism is an inherited condition caused by a recessive allele. Individuals 1 and 2 are parents; 3, 4,…

DNA contains pairs of bases. Which pair shows a correct combination of bases? A A and C B C and G C G and A D T and G

The following are involved in protein synthesis. 1 amino acids assembled in order 2 mRNA moves to the cytoplasm 3 mRNA passing through a ribosome 4 DNA in the nucleus In which…

A man of genotype IAIo and woman of genotype IBIo have a child. What is the chance that the child will have the same blood group as one of its parents? A zero B 1 in 4 C 1 in 2 D…

A man who has red-green colour blindness has a child with a woman who does not have red-green colour blindness. The child has red-green colour blindness. The man and woman decide…

Fig. 5.1 shows the stages involved in protein synthesis, with parts labelled X, Y and Z, and DNA and amino acid indicated. State the names of the parts labelled X, Y and Z in Fig.…

Fig. 2.1 is a diagram of part of a DNA molecule. Draw a circle on Fig. 2.1 to identify one pair of bases.

Two parents have the genotypes Bb and bb for a particular feature. What is the probability of these parents having offspring that are homozygous recessive for this feature? A 100%…

A genetic cross between two organisms may be shown as Tt × Tt. What does T represent? A a dominant allele B a dominant chromosome C a recessive allele D a recessive chromosome

Why are cells in the pancreas the only body cells that produce insulin? A All of the genes in the nucleus of a cell in the pancreas are expressed. B Other body cells do not have…

Red-green colour blindness is a sex-linked characteristic caused by a recessive allele. Which prediction can be made about the children of a woman who is colour-blind and a man…