Chapter 17 - Inheritance Flashcards
What is inheritance?
Inheritance is the transmission of genetic information from generation to generations.
What are chromosomes?
Chromosomes are made of DNA, which contains genetic information in the form of genes.
What is a gene?
A gene is a length of DNA that codes for a proteins.
What is an allele?
An allele is an alternate form of a gene.
What chromosomes do humans have?
Females have XX chromosomes whereas males have XY chromosomes.
How does DNA make proteins?
The sequence of bases in a genes determines the sequence of amino acids used to make a specific protein.
Diagram of a punnet square
What is transcription?
Transcription is the process of rewriting the base code of DNA into bases of RNA.
What is translation?
Translation is the process of using RNA base sequences to build amino acids into sequence in a protein.
How does DNA control cell function?
DNA controls cell function by controlling the production of proteins including enzymes, membrane carriers, and receptors for neurotransmitters.
What is the process of protein synthesis?
- The gene coding for the protein remains in the nucleus.
- Messenger RNA (mRNA) is a copy of a gene.
- mRNA molecules are made in the nucleus and move to the cytoplasm.
- The mRNA passes through ribosomes.
- The ribosome assembles amino acids into protein molecules.
- The specific sequence of amino acids is determined by the sequence of bases in the mRNA.
Do body cells contain the same genes?
Most body cells in an organism contains the same genes, but many genes in a particular cell are not expressed because the cell only make the specific proteins it needs.
What is a haploid nucleus?
A haploid nucleus contains a single set of chromosomes (23 in humans).
What is a diploid nucleus?
A diploid nucleus contains two sets of chromosomes (46 in humans). In a diploid cell, there is a pair of each type of chromosome and in a human diploid cell there is 23 pairs.
What is mitosis?
Mitosis is a type of nuclear division giving rise to genetically identical cells.
What is the process of mitosis?
- Each chromosome in the nucleus copies itself exactly and forms ‘x’ shaped chromosomes.
- Chromosomes line up along the centre of the cell where cell fibres pull them apart.
- The cell divides into two genetically identical cells and each new cell has a copy of each of the chromosomes.
What is the process of meiosis?
- Each chromosome makes identical copies of itself and forms ‘x’ shaped chromosomes.
- First division: chromosomes pair up along the centre of the cell, recombination occurs and then cell fibres will pull the pairs apart, each new cell will have on of each recombinant chromosome pair.
- Second division: chromosomes will like up along the centre of the cell, cell fibres will pull them apart.
- A total of four haploid daughter cells will be produced.
What are the differences between mitosis and meiosis?
Example of a punnet square
How are test crosses used?
Breeders can use test crosses to find out the genotype of an organism showing the dominant phenotype. This involves crossing the unknown individual with an individual showing the recessive phenotype. If the individual is showing the recessed phenotype, then its genotype must be homozygous recessive.
What is codominance?
Codominance is a situation in which both alleles in a heterozygous organism contribute to the phenotype. Blood type is an example of codominance:
What are sex linked characteristics?
Sex-linked characteristics is a feature in which the gene responsible is located on a sex chromosome and that this make the characteristic more common in one sex than in another. Red-green colour blindness is an example of sex-linkage.
