2.2 Chromosomes, Genes and DNA. Flashcards
What are basic biological units known as?
Cells.
List some examples of cells.
skin cells
stem cells
blood cells
nerve cells
fat cells
muscle cells.
What does DNA stand for?
deoxyribonucleic acid
Where is DNA located in the cell?
The nucleus.
What is hierarchical relationship between Cells, Nuclei, Chromosomes, Genes, DNA, Nucleotides
Biggest to smallest (for lack of a better term)
What are genes made up of?
Sections of DNA.
Each genetic instruction that codes for a particular ____ is called a gene.
Trait
What is the location of a gene on a specific chromosome called.
Locus
Genes that are located on the same chromosome are described as being ____
Linked.
What do genes do?
They contain the instructions for making a particular protein (polypeptide)
How many chromosome do most people have?
46
Why aren’t chromosomes visible when cells aren’t divided?
It is because the coils are unwound and the DNA is spread throughout the nucleus.
What are chromatids?
They are two identical threadlike strands that the chromosome divides into during cell division.
Are sister chromatids identical?
YES
What is the centromere (in the chromosome)?
It is the region where two sister chromatids and the long and short arms of the chromosomes join.
What is the telomere (in the chromosome)?
It is the cap on the end of each chromosome.
What is the kinetochore (in the chromosome)?
It is associated with the centromere and assists with cell division.
Where are each (4) parts of the chromosome located.
Centromere - Middle
Telomere - Ends of the chromosomes.
Chromatids - made up of half of the chromosome (one short and one long arm)
Kinetochore - Around the centomere.
Image link:
https://content2.learnon.com.au/secure/ebooks/97807303/9780730386926/images/lightwindow/c02f08.png
Differences between autosomes and sex chromosomes.
Sex chromosomes:
- Either X or Y.
- Only 2 in the body.
- Differ between men and women.
Autosomes:
- All present in a regular person.
- 44 total.
- Present in both men and women.
What are somatic cells?
Non-sex cells.
How are autosomes organised?
Organised into 22 pairs on the basis of their relative size, position of centromere and stained banding patterns.
Chromosome 1: Largest.
Chromosome 22: Smallest.
What are the members of matching pairs of chromosomes described as?
Homologous.
What do sex chromosomes determine?
Gender (sex)
What are XY and XX chromosomes mean?
XY: Male
XX: Female
What is a karyotype?
It is an image that orders chromosomes based on size.
What are mitosis and meiosis and what is the difference?
These are two types of cell division involved in cell production.
Mitosis is used in somatic cells for replacement, growth and repair.
Meiosis is used in sex cells to produce to new gametes (sperm and ova).
What is the difference in the result of meiosis compared to mitosis?
Meiosis results in the chromosome number being halved meaning only one chromosome from each pair in created.
How is genetic information passed on in fertilisation?
23 chromosomes in the sperm and 23 in the ova. They fuse together during fertilisation to make 23 pairs (one chromosome from each parent).
