Grade 10 science exam DNA and Genetics part 1 Flashcards
What is the structure of DNA
A double helix made of two strands twisted together.
What are the 4 nitrogen bases in DNA
Adenine (A), Thymine (T), Cytosine (C), and Guanine (G).
which base pairs match together DNA
- Adenine (A) pairs with Thymine (T)
- Cytosine (C) pairs with Guanine (G)
What is the back bone of DNA made up of?
Sugar (deoxyribose) and phosphate molecules.
What is a nucleotide
a molecule that is the basic unit of DNA and RNA.
Where is DNA found in a cell
In the nucleus (in chromosomes) and in small amounts in mitochondria.
What is the role of DNA
It stores genetic information that determines an organism’s traits and directs protein synthesis.
What is a gene
A section of DNA that codes for a specific protein.
How does DNA replicate?
DNA unzips, and new nucleotides pair with the exposed bases to create two identical strands.
What is a chromosome
A long, coiled structure of DNA that contains many genes.
How many chromosomes do humans have
46 chromosomes (23 pairs) in each cell.
What is RNA
RNA is a single-stranded molecule that helps make proteins. It has uracil (U) instead of thymine (T) and uses ribose sugar.
What is the function of messenger RNA (mRNA)?
It carries genetic information from DNA to ribosomes for protein synthesis.
what is the building blocks of DNA?
Nucleotides (sugar, phosphate, and nitrogenous base).
What is a somatic cell
Body cells that contain the full set of chromosomes (diploid).
How do somatic cells reproduce?
Through mitosis (cell division for growth and repair).
What is mitosis
A type of cell division that produces two identical daughter cells for growth and repair.
What happens in metaphase in mitosis
Chromosomes line up in the middle of the cell.
what happens in anaphase in mitosis
Chromosomes are pulled apart to opposite sides of the cell.
What is meiosis?
A type of cell division that creates gametes (sperm and egg cells) with half the number of chromosomes.
How many chromosomes do gametes have?
23 chromosomes (haploid), half the number of a somatic cell.
Why is meiosis important?
It creates genetic variation and ensures offspring have the correct chromosome number.
How is meiosis different from mitosis?
*Mitosis: Produces 2 identical diploid cells for growth/repair.
*Meiosis: Produces 4 unique haploid cells for reproduction.
What is a karyotype
A picture of all the chromosomes in a cell, arranged in pairs.
What is the purpose of a karyotype?
To check for chromosome abnormalities, like Down syndrome.
How many chromosomes are in a normal human karyotype?
46 chromosomes (23 pairs).
what is an allele
each of two or more alternative forms of a gene that arise by mutation and are found at the same place on a chromosome.
