Chromosome & Cell Division 2 Flashcards
<p>What are the stages of the cell cycle?</p>
<p>Interphase and mitosis</p>
<p>What are the different stages of interphase?</p>
<p>G1, S and G2</p>
<p>What happens during the G1 stage of interphase?</p>
<p>Protein and RNA synthesisGrowth and maturation of the cell occurs
DNA checking and subsequent repair occurs during the pause between G1 and S</p>
<p>What happens during the S phase of interphase?</p>
<p>DNA synthesis</p>
<p>What happens during the G2 phase of interphase?</p>
<p>Further synthesis of RNA and proteins
Further growth
Organelles such as mitochondria grow and divide
Followed by proof reading and subsequent repair of newly synthesised DNA</p>
<p>What are the stages of Mitosis?</p>
<p>Prophase
Metaphase
Anaphase
Telophase
Cytokinesis</p>
<p>What happens during Prophase?</p>
<p>Chromosomes condense
Nuclear membrane disappears
Spindle fibres form from the centriole</p>
<p>What happens during metaphase?</p>
<p>Chromosomes allign at the equator of the cell
Attached by fibre to each centriole
Maximum condensation of chromosome</p>
<p>What happens during anaphase?</p>
<p>Sister chromatids separate at the centromere
Move to opposite ends of the cell</p>
<p>What happens during telophase?</p>
<p>Nuclear membranes form</p>
<p>What happens during cytokinesis?</p>
<p>Cytoplasm separates</p>
<p>What is the structure of the centromere?</p>
<p>Repetitive DNA sequences (satellite DNA
)Site of the kinetochore which is a protein complex that binds to microtubules</p>
<p>What is the difference between Heterochromatin and Euchromatin?</p>
<p>Heterochromatin :
- is condensed structure
- Silenced genes
Euchromatin :
- Open structure
- Active genes</p>
<p>Where can you find satellite DNA and what is it?</p>
<p>Tandemly repeated DNA sequences at the Centromeres and telomeres of chromosomes</p>
<p>How is chromatin formed?</p>
<p>DNA packed within histone proteins </p>
<p>What is the charge of histone?</p>
<p>Positively charged</p>
<p>What is a nucleosome?</p>
<p>A unit of eukaryotic chromosome
A length of DNA wrapped around a core of histones</p>
<p>How is a solenoid structure formed?</p>
<p>Further wrapping of nucleosomes</p>
<p>What are the different levels of structural elements of chromatin?</p>
<p>Nucleosome
Chromatin fibre
Fibre-scaffold complex
Chromosome</p>
<p>What is the purpose of packaging DNA?</p>
<p>Charge neutralised
Takes up less space
Inactive DNA can be folded into inaccessible locations until required</p>
<p>What is the purpose of FISH (fluorescent In Situ Hybridisation)</p>
<p>Mark or tag a specific DNA sequence out of the whole genome</p>
<p>What is the process of FISH?</p>
<p>Denature DNA into single strands
Hybridise the DNA with fluorescent tag (tag complimentary to desired DNA sequence)
Excess tags are washed away
Tags are either fluorescent themselves or can attach to a fluorescent molecule
The chromosome is then viewed under a fluorescence microscope revealing the physical location of the desired gene</p>
<p>What are the different types of FISH probes?</p>
<p>Unique sequence probes
Centromeric probes
Telomeric probes
Whole chromosome probes</p>
<p>What are the stages of meiosis?</p>
<p>DNA replication
Pairing of homologous chromosomes
Recombination takes place
Homologous chromosomes are separated by spindle fibres
Cell division 1
Meitoic division 2 takes place</p>
<p>What is the purpose of meiosis?</p>
<p>It is the cell division of germ cells to form haploid gamete cells from diploid cells in ovaries and testes</p>
<p>What are the different names given to egg formation and sperm formation?</p>
<p>oogenesiss
permatogenesis</p>
<p>When does gametogenesis begin in males and females?</p>
<p>Males - Puberty
Females - Early embryonic life</p>
<p>What determines the sex of the zygote?</p>
<p>Wether or not the sperm contains the y chromosome</p>
<p>Where does mitochondrial DNA come from?</p>
<p>Only from the mother via the egg</p>
<p>What happens to the X chromosome in females?</p>
<p>One of them is randomly inactivated</p>
