Genetics Test Revision Flashcards
Where is DNA found and why is it important?
DNA is found in the nucleus and contains the genetic information for an organism’s growth and development.
Explain how DNA, Chromosomes and Genes are interrelated.
Chromosomes carry DNA in cells. DNA is responsible for building and maintaining your human structure. Genes are segments of your DNA, that give you the physical characteristics that make you unique. They work together to make you who you are.
Describe the structure of DNA.
DNA is like a twisted ladder. The phosphate and sugar on the sides of the DNA make up the sugar-phosphate backbone. Strong covalent bonds hold the sugar of one nucleotide to the phosphate of the next. These paired strands coil up into a double helix.
What is a chromosome?
Chromosomes are DNA packaged tightly into thread-like structures and coiled many times around proteins called histones.
What is a homologous chromosome?
Homologous chromosomes contain the same type of genetic information. One chromosome comes from the male parent and the other from the female parent.
What is a diploid cell?
Contain two sets of chromosomes and undergo mitosis.
What is a haploid cell?
Contain only one set of chromosomes - undergo meiosis.
What is a karyotype?
The general appearance of a complete set of chromosomes in the cells of a species.
What are the phases of mitosis?
Interphase, Prophase, Metaphase, Anophase, and Telophase/Cytokinesis.
What happens in interphase during Mitosis?
Preparation for mitosis through cell growth, DNA replication
What happens in prophase during Mitosis?
The nuclear membrane disintegrates, chromosomes condense and become visible, mitotic spindle begins to form.
What happens in Metaphase during Mitosis?
Chromosomes line up in the middle of the cell.
What happens in Anophase during Mitosis?
Sister chromatids are pulled apart to when spindles contract.
What happens in Telophase during Mitosis?
The nuclear membrane reforms around each set of chromosomes, cytokinesis begins and two nuclei form.
What is the purpose of mitosis?
For the repair, maintenance, growth, development and functioning of a living organism. Responsible for the creation of all somatic cells in the body.
What happens in Interphase during Meiosis 1?
DNA replication and the cell enters the reproductive cycle with 4 copies of each chromosome.
What happens in Prophase during Meiosis 1?
Chromosomes pair up in homologous pairs and crossing over occurs. The DNA condenses around histones—the nuclear membrane reforms.
What happens in Metaphase during Meiosis 1?
Homologous chromosomes line up in the middle of the cell and random assortment occurs.
What happens in Anophase during Meiosis 1?
Homologous chromosomes are pulled apart to opposite poles of the cell when the spindles contract.
What happens in Telophase during Meiosis 1?
The nuclear membrane reforms and cytokinesis begins resulting in 2 haploid daughter cells.
What happens in Prophase during Meiosis 2?
DNA condenses and chromosomes become more visible—the nuclear membrane disintegrates and the centrioles migrate.
What happens in Metaphase during Meiosis 2?
Sister chromatids line up in the centre of the cell and spindles form.
What happens in Anophase during Meiosis 2?
Sister chromatids are pulled apart to opposite poles of the cell and spindles contract.
What happens in Telophase during Meiosis 2?
The nuclear membrane reforms around the sister chromatids. Cytokinesis begins resulting in 4 non-identical haploid daughter cells, each genetically different.
