Cell division and Genetics/Inheritance - Tutorial 6
No description yet. This curated deck is ready for daily study.
Card preview (13)
Define the terms, alleles, homozygous alleles & heterozygous alleles
• Alleles - are alternative versions of a gene • Homozygous alleles - have identical information for a trait • Heterozygous alleles - have different information for a trait
Name & describe the two different types of cell division
Somatic cell division: - Aim is to replicate cells to replace dead or injured cells or add new cells during tissue growth - Occurs through mitosis and cytokinesis Reproductive cell division: - Aim is to produce the gamete cells (sperm and oocyte) required for the next generation Occurs through meiosis
Explain how genetic variation occurs
Crossing over increases genetic variation, occurs in meiosis and is the exchange of genes between homologous (paired) chromosomes
Define cancer and the terms malignant & benign tumours
Cancer: is the group of diseases that results from uncontrolled or abnormal cell proliferation Malignant: Malignant tumours undergo metastases (the spread of cancerous cells to other parts of the body) Benign tumours do not metastasise (they do not spread)
Name the type of cancer that arises from the following tissues
Epithelial tissue - Carcinoma Melanocytes - Melanoma Lymphatic tissue - Lymphoma Leukocytes - Leukaemia
State three causes of cancer
• Environmental agents, eg. Chemicals and radiation • Viruses, eg. human papillomavirus (HPV) causes cervical cancer by stimulating abnormal proliferation of cells • Genes, eg. abnormalities of the genes that control and regulate cell division
Define the following terms; inheritance, genetics, genotype, phenotype, mutation, autosomes & x-linked (sex) chromosomes
Inheritance - passing of genetic traits to another generation Genetics - branch of biology that deals with inheritance Genotype - genetic makeup of an individual Phenotype - Physical characteristics of an individual, determined by genotype and environment Mutation - permanent change in a gene Autosomes - any chromosome other than sex chromosomes Sex chromosomes - the 23rd pair of chromosomes females have XX and males have XY
Define multiple allele inheritance and give one example of a genetic trait carried by this type of inheritance
• Genes with more than two alternate forms Example: 3 different alleles of the I gene, IA, IB or i
Define complex inheritance and give one example of a genetic trait carried by this type of inheritance
• Most inherited traits are not controlled by on gene but by: the combined effects of two or more genes or combined effects of many genes and environmental factors -Height: malnutrition, disease
Describe the difference between autosomes & sex chromosomes
• Autosomes - are any chromosomes other than a sex chromosomes • Sex chromosomes - are the 23rd pair In females, the 23rd pair consists of XX In males, the 23rd pair consists of XY
Explain why many x-linked conditions primarily affect males
More common in men as they have only one X chromosome
Give two examples of x-linked conditions
• Haemophilia • Colour Blindness
Explain the terms trisomy & monosomy and give an example of a condition for each
Trisomy: 2n+1, has an extra chromosome, down syndrome Monosomy: 2n-1, is missing a chromosome, turner syndrome