Genes and DNA

Question 1

What is a gene?

Answer 1

sequence of nucleotides that codes for rRNA, tRNA or single polypeptide via an mRNA intermediate.
eukaryotes have more than 1 copy of some genes while prokaryotes have only 1 copy.

Question 2

what is euchromatin?

Answer 2

eukaryotic genes that being actively transcribed by a cell

Question 3

what is heterochromatin?

Answer 3

genes that are not being actively transcribed.

Question 4

what is genome?

Answer 4

entire DNA sequence of an organism

Question 5

what is the central dogma?

Answer 5

the central dogma is that DNA is transcribed to RNA which is translated to aa forming a protein.

Question 6

what does DNA stand for ?

Answer 6

deoxyribonucleic acid

Question 7

what is DNA?

Answer 7

Polymer of nucleotides. DNA nucleotides differ from each other only in the nitrogenous base.

Question 8

what are the 4 nitrogenous bases of DNA?

Answer 8

Adenine, Guanine, Cytosine and Thymine.
A and G are two rings and called purines.
C and T are single ring and called pyrimidines.

Question 9

how are nucleotides connected?

Answer 9

phosphodiester bond between the third carbon of one deoxyribose and the 5 carbon of the other. creates a sugar to a phosphate bond. DNA is made in a 5’ to a 3’ direction

Question 10

DNA strands

Answer 10

are in antiparallel direction bound together by hydrogen bonds between the bases to form a double stranded structure . A and T form 2 hydrogen bonds with each other. G and C form 3 hydrogen bonds with each other. the two DNA strands are complementary strands, they curl into a double helix.

Question 11

what are the two grooves?

Answer 11

the double helix has two distinct grooves, the major and the minor.

Question 12

what is each nucleotide made up of ?

Answer 12

a phosphate group
a 5 carbon sugar 
and a nitrogenous base. 
know that AT pair and GC pair 
and that RNA docent have T it has U or Uracil instead ( which is a pyrimidine)

Question 13

what does RNA stand for ?

Answer 13

ribonucleic acid

Question 14

how is RNA different from DNA?

Answer 14

Carbon 2 on pentose is not deoxygenated ( it has a OH hydroxyl group)
RNA is single stranded
RNA has U. instead of T
RNA can also move through nucleus pores and is not confirmed to the nucleus.
DNA is made by replication and RNA is made by transcription.

Question 15

what are 3 important types of RNA?

Answer 15

mRNA (messenger)- deliver DNA code for amino acids to the cytosol where proteins are made
rRNA (ribosomal)- combines with proteins to form ribosomes. - rRNA is made in the nucleolus.
tRNA (transfer) - collects amino acids in the cytosol and transfers them to ribosomes for incorporation into a protein.