Topic 4- DNA, genes and chromosomes

Question 1

How is DNA stored in eukaryotic cells?

Answer 1

-Linear DNA molecules that exist as chromosomes

Question 2

How is DNA arranged in eukaryotic cells?

Answer 2

-Thread like structures
-Each made up of one long molecule of DNA and it’s associated proteins

Question 3

Where are chromosomes found?

Answer 3

In the nucleus

Question 4

What is a DNA molecule wrapped in?

Answer 4

-Histone protein

Question 5

What is the function of a histone proteins?

Answer 5

-To support the DNA

Question 6

How is a chromosome formed?

Answer 6

-The DNA and protein is coiled up very tightly to form a compact chromosome

Question 7

Which organelles have their own DNA?

Answer 7

-Chloroplast
-Mitochondria

Question 8

Why is the DNA in chloroplast and mitochondria similar to prokaryotic DNA?

Answer 8

-Circular
-Shorter than DNA molecules in the nucleus
-Not associated with histone proteins

Question 9

What are the main differences between prokaryotic and eukaryotic DNA

Answer 9

-The DNA molecules are shorter and circular
-Is not wound around histones
-Condnses by supercoiling

Question 10

What is the main similarity between eukaryotic and prokaryotic DNA?

Answer 10

-Carry DNA as chromosomes

Question 11

What is a gene?

Answer 11

-A sequnce of DNA bases that code for either a polypeptide or functional RNA

Question 12

What does the order of the bases in a gene determine?

Answer 12

-The order of the amino acids in a particular polypeptide

Question 13

Genes that don’t code for polypeptides code for what instead?

Answer 13

-Functional RNA

Question 14

What is functional RNA?

Answer 14

-RNA molecules other than mRNA which perform special task in protein synthesis

Question 15

Give an example of a functional RNA molecule

Answer 15

-tRNA
-rRNA

Question 16

What is a proteome?

Answer 16

-The full range of proteins that the cell is able to produce

Question 17

What is a genome?

Answer 17

-The complete set of genes in a cell

Question 18

What are introns?

Answer 18

-Genes that do not code for polypeptides contain sections that do not code for amino acid

Question 19

What are exons?

Answer 19

-Gens that do code for amino acids

Question 20

What are non-coding multiple repeats?

Answer 20

-DNA sequences that repeat over and over again that do not code for amino acids

Question 21

What is an allele?

Answer 21

-One of two or more versions of DNA sequence (a single base or a segment of bases)

Question 22

How many pairs of chromosomes do humans have?

Answer 22

23 pairs (46 in total)

Question 23

Why do homologous chromosomes pair up?

Answer 23

-They are both the same size
-Have the same genes (may have different alleles)

Question 24

Where will allele coding for the same characteristic be found?

Answer 24

-At the same fixed position (Locus)

Question 25

What is the bond between the phosphate and the pentose sugar called?

Answer 25

-Ester bond

Question 26

What is the bond between the base and pentose sugar called?

Answer 26

-Glycosidic

Question 27

What are the bonds between nucleotides called?

Answer 27

-Phosphodiester

Question 28

How many amino acids are there?

Answer 28

-20

Question 29

How many bases are there?

Answer 29

-4

Question 30

How many triplets are there?

Answer 30

-64 including ( 3 stop and start triplets)

Question 31

What does generate mean?

Answer 31

-More than one triplet code for a specific amino acid

Question 32

What does universal mean?

Answer 32

-The same triplet codes for the same amino acid in every species

Question 33

What does non-overlapping mean?

Answer 33

-Each triplet is distant from each other

Question 34

What are the names of the triplet in mRNA and tRNA?

Answer 34

-mRNA=codon
-tRNA= anticodon

Question 35

When does DNA condense?

Answer 35

-Prophase

Question 36

Why is there a different number of nucleotides after transcription?