2.2 terms - Replicating Cells (DNA AND GENETICS) Flashcards
What is
DNA replication? What does it create?
DNA replication is the process of replicating a genome’s DNA. It replicates its chromosome, and results in two identical DNA molecules (sister chromatids).
What are the steps in DNA replication?
1) First, the strands of the double helix will seperate from eachother and expose their bases
2) Then individual nucleotides from the nucleus that aren’t part of a DNA chain yet will come, and pair up with the exposed bases following complementry pairing. The sugar and phosphate molecules will bond with their neighbouring nucleotides, forming new DNA strands
What is
chromatid?
It is one of the strands of a chromosome that has undergone replication.
What is
mitosis?
Mitosis is the cell replication process. Mitosis produces diploid daughter cells identical to the parent cell, and is the method used for general growth, tissue repair, tissue regeneration, and asexual reproduction.
Most unicellular organisms reproduce through ____, while most multicellular organisms reproduce through _____.
Mitosis, meiosis
Mitosis is a continuous process. What are its stages?
1) Interphase - The chromosomes replicate to have 2 chromatids.
2) Prophase - Chromosomes become visible.
3) Metaphase - The membrane surrounding the nucleus breaks down. The replicated chromosomes line up along the cell’s equator, and a network of fibres appear, extending from each pole of the cell to each chromosome.
4) Anaphase - The fibre network contracts and seperates the sister chromatids from eachother, pulling chromosomes to each pole of the cell.
5) Telophase - A new nuclear membrane encloses the chromosomes at each pole.
6) Cytokinesis - The cytoplasm divides, resulting in 2 identical daughter cells both containing a full diploid set of chromosomes.
What is
asexual reproduction?
Asexual reproduction is a process used by most unicellular-organisms-with-a-nucleus to reproduce without the use of gametes. It is done through mitosis, and makes the offspring an identical clone of its parent organism.
What are some examples of organisms that use asexual reproduction?
- Plants (eg. grass, hydra)
- Yeast (eg. Candida)
- Animals
- Algae (eg. Volvox)
- Protists (eg. amoeba)
What is
a centromere?
It is the region of a chromosome where the two chromatids are attached.
What is
a zygote?
It is the cell formed by the union of two gametes (the sperm and the egg)
What is
diploid number?
The diploid number is the number of chromosomes in diploid cells. It is also known as 2n (meaning 2 sets - that’s two sets of autosomes and two sex chromosomes)
what is
haploid number?
It is the number of chromosomes in a haploid cell. Haploid cells only contain 1 copy of each chromosome, and this number is also called ‘n’.
