Block 1: Nucleic acids and genetic information: week 2 Flashcards
what is Chromatin?
Chromatin is loosly packed DNA strands found in the nucleus.
what is a Nucleosome?
Nucleosomes are units of dna that make up chromatin.A Nuclosome structure is DNA wrapped around a histone protein twice witth a linker DNA connecting the them together.
What happens to chromatin when the cell is about to undergo division?
The chromatin condenses more tightly by continous coiling and wraping around itself to then form chromosome.
What is the human karyotype?
The karyotype is the sterotypic number, shape and size of chomosomes during metaphase.
how many chomosomes are there?
there are 46 chromosomes in total
23 paternal and 23 maternal
How many sex chromosomes are there?
you inherit 1 sex chromosome from each parent ( maternal and perternal) so of the 23 chromosomes 1 is a sex chromosome.
what the name of a chromosome that is not a sex chromosome?
This is called an autosome.
what is a telomere?
A telomere is the ends of the chromosome that protect it.
where is the p arm?
the upper part of the chomosome
where is the q arm?
The q arm is the btoom half of the chromosome.
What is the centromere?
center of the chromosome and is also where spindle attachment occurs.
what is the promoter region?
The promoter region is where transcription factors attch to control transcrption.
what are transcrption factors?
Transcription factors influnce gene expression by regulating RNA activity.
what causes cyctic fibrosis?
Cystic fibrosis is a disease that is caused by an abnormal gene. An abnormal gene is called a genetic mutation. The gene that causes problems in CF is found on the seventh chromosome.
what causes down syndrome?
children are born with an extra chromosome of chromosome 21.
What is klinefelter syndrome?
Klinefelter syndrome is where boys and men are born with an extra X chromosome.
what are the steps in a cell cycle?
The cell cylce has the mitotic phase and interphase.
What are the phases in interphase?
G1 G0 S1 and G2
What happens at each of the phases of interphase?
G0- cell isnt dividing, its resting until it receives a signal to enter the cycle.
G1- cell grows, increased amount of oganells, increased protein synthesis
S1- DNA in cell duplicates to prepare for division
G2- cell onstious to grow futher and undergoes checks to ensure its ready for mitosis.
what can have an effect on mitosis?
medical procedures such as chemotherapy
or
medications ( drugs)
what happens during mitosis? (inluding each step)
Prophase-chromosome condensation, disperal of the nuceli .centriols split and move to each poll and spindles start to form
Prometaphase- nuclear evelope fragmentation, attachment opf spindles to centromeres on chromosome.chromosomes start to move to the center.
Metaphase- chromosomes alligment at the metaphase plate
Anaphase- chromosomes move to opposite cell plates(polls)
Telophase- chromosomes uncoil, nucleoli develop and fuse, disassembly of spindle and reformation of nuclear envelope.
cytokinesis- cytoplasm divides and two daughter cells are formed as a result.
what is a nucleotide?
nucleotide is a molecule consisting of a nitrogenous base, phosphate group and sugar residual.
How man bases are there for nucleotides?
There are 4 bases guanine adenine cytosine thymine (uricil in RNA)
How many hydrogen bonds are found between each of the bases?
adenine and thymine have 2 hydrogen bonds between them.
cytosine and guanine have 3 hydrogen bonds between them.
