Topic 5: Heredity

Most reptiles, birds and mammals breed on land and use internal fertilisation. Which statement best explains an advantage of internal fertilisation for these animals?

A Year 12 class in Dubbo watches a pair of frogs in a farm dam: the female releases thousands of eggs into the water and the male releases sperm over them. Which statement describes a disadvantage of this method of fertilisation?

Which statement about binary fission in bacteria is correct?

A winemaker in the Barossa Valley looks at yeast, a single-celled fungus, under a microscope and sees small cells attached to the sides of larger cells. Which process is shown, and what is true of the small cells?

Bread mould spreads across a loaf in a few days and soon appears on other food in the same cupboard. Which feature of the fungus's reproduction best explains this?

A grower near Coffs Harbour produces new strawberry plants from the runners of one high-yielding plant instead of from seed. What is the main consequence?

In a flowering plant, which sequence of events leads to the formation of a seed?

Which statement correctly describes implantation in humans?

Early in pregnancy, cells of the embryo secrete human chorionic gonadotrophin (hCG). What is its main role?

During labour, stretching of the cervix triggers the release of oxytocin, which strengthens contractions of the uterus, which stretch the cervix further. What does this sequence show?

A dairy farmer near Bega uses artificial insemination with semen from one bull whose daughters give high milk yields. Over many generations, what is the main risk for the herd?

In a sample of double-stranded DNA from a eucalypt leaf, 28% of the bases are adenine. What percentage of the bases are guanine?

Which statement describes how the two strands of a DNA molecule are held together?

A student builds a model of one DNA nucleotide. Which three parts must the model include?

Bacteria whose DNA contains only heavy nitrogen (15N) are moved to a medium containing only light nitrogen (14N) and each divides once. What does each new DNA molecule contain?

During DNA replication, what is the role of DNA polymerase?

Body cells of the onion plant have 16 chromosomes (2n = 16). A cell in an onion anther divides by meiosis. How many cells are formed, and how many chromosomes does each contain?

Which event in meiosis exchanges sections of DNA, and so alleles, between the chromatids of a homologous pair?

A cut in the stem of a lemon-scented gum seedling heals as new cells form at the wound. Which statement about the new cells is correct?

Why is it important for the continuity of a species that DNA is copied accurately before cells divide?

Which comparison of the DNA in a bacterium and in a human cell is correct?

What is a plasmid?

In a eukaryotic cell, where do transcription and translation take place?

The template strand of part of a gene reads 3' TAC CGA TTG 5'. What is the sequence of the mRNA transcribed from this part of the gene?

The coding sequence of an mRNA molecule, from its start codon to its stop codon inclusive, is 300 nucleotides long. How many amino acids are in the polypeptide it codes for?

What is the role of tRNA in translation?

Before a eukaryotic mRNA leaves the nucleus, the introns are removed. What are introns?

Haemoglobin is made of four polypeptide chains, each folded into its own shape, that fit together into one protein. Which level of protein structure describes how the four chains fit together?

Which pair correctly matches a protein with its function?

Himalayan rabbits have white fur on the body and black fur on the ears, nose and feet. When fur on the back is shaved and an ice pack is kept on the patch while the fur regrows, the new fur is black. What does this show?

In a Blue Mountains garden, cuttings taken from one hydrangea plant are grown in two beds. Plants in the acidic bed flower blue and plants in the alkaline bed flower pink. Which conclusion is best supported?

In pea plants, the allele for purple flowers (P) is dominant to the allele for white flowers (p). Two heterozygous plants are crossed. What percentage of the offspring are expected to have white flowers?

A farmer near Armidale owns a black Angus bull. In Angus cattle the allele for black coat (B) is dominant to the allele for red coat (b). Which cross and result would show that the bull is heterozygous?

Shorthorn cattle with one allele for red hair and one allele for white hair have a roan coat, in which red hairs and white hairs are mixed. Which inheritance pattern does this show?

In snapdragons, a cross between a red-flowered plant and a white-flowered plant gives only pink-flowered plants. Two of the pink plants are crossed. What ratio of flower colours is expected in their offspring?

Haemophilia A is an X-linked recessive disorder. A woman who is a carrier (XH Xh) and a man without haemophilia (XH Y) have a son. What is the probability that their son has haemophilia?

Red-green colour blindness is X-linked recessive. A colour-blind man has children with a woman who carries no colour-blindness allele. Which statement about their children is correct?

A woman with blood group A and a man with blood group B have a child with blood group O. What are the parents' genotypes?

Which statement about the ABO blood group gene in humans is correct?

In a family studied by a genetic counsellor, two parents who do not have a condition have three children, and one of their daughters has the condition. Which inheritance pattern is shown?

What is a single nucleotide polymorphism (SNP)?

A study of 250 plants of a native wildflower recorded their genotypes at one gene: 90 were RR, 120 were Rr and 40 were rr. What is the frequency of allele r in this sample?

A plant has the genotype AaBb, and the two genes are on different chromosomes. How many genetically different kinds of gamete can it produce for these two genes?

Which processes give offspring of sexual reproduction new combinations of alleles?

Students crossed two fruit flies heterozygous for wing shape and counted 61 offspring with normal wings and 14 with vestigial wings. They expected a 3 : 1 ratio. What would most improve the reliability of their ratio?

In gel electrophoresis for DNA profiling, why do the DNA fragments move through the gel?

DNA profiling compares short tandem repeats (STRs) at several loci. Why are STRs useful for identifying individuals?

Keepers at a wildlife park want to know which of three male koalas fathered a joey. The table gives the number of repeats in each allele at three STR loci. Which male is the father?

What does DNA sequencing determine that DNA profiling does not?

In a hypothetical study, ecologists measured mean heterozygosity (the proportion of loci at which an animal carries two different alleles) in three isolated colonies of brush-tailed rock-wallabies. Which management action do the data best support?

Why is mitochondrial DNA used to trace the maternal ancestry of human populations?

A study of 40 families with an inherited disorder found that every affected child had at least one affected parent, and that males and females were affected in equal numbers. Which inheritance pattern do these data best support?

A large international project sequenced the genomes of thousands of people from many populations. Which is a valid use of such data?

Ella's father has haemophilia A, an X-linked recessive condition. Ella and her partner Sam are both unaffected by haemophilia and by cystic fibrosis, an autosomal recessive condition. Their first child, a daughter, has cystic fibrosis. What is the probability that their next child is a son who has both haemophilia and cystic fibrosis?

In a hypothetical class investigation, students grew garlic root tips in water containing chemical X at four concentrations. From each concentration they squashed and stained one root tip, and in one field of view counted all the cells and the cells in a stage of mitosis. The mitotic index is the cells in mitosis divided by the cells counted. Which conclusion do the data and the method best support?

In a hypothetical trial, a plant breeder near Wagga Wagga crossed two wheat varieties. In group 1 she removed the anthers from 50 florets of variety P before they shed pollen, covered the florets with paper bags, and later dusted them with pollen from variety Q. Group 2 had the same treatment but was given no pollen. Group 3 was 50 untreated florets of variety P. Which conclusion about the method do the results support?