bio mol - compare questions

Question 1

similarities between ATP and DNA nucleotides

Answer 1

Both contain adenine
Both contain phosphate group
Both have pentose sugar

Question 2

differences between ATP and DNA nucleotides

Answer 2

ATP has 3 phosphate groups; DNA nucleotide only has 1

ATP always has adenine, DNA nucleotide could contain thymine, cytosine or guanine

ATP contains ribose, DNA contains deoxyribose

DNA nucleotides can polymerise (form polymers), ATP cannot

Question 3

similarities between mRNA and tRNA

Answer 3

Both contain RNA nucleotides – adenine, guanine, cytosine and uracil

Both produced in the nucleus

Both contain phosphodiester bonds

Question 4

differences between mRNA and tRNA

Answer 4

mRNA has codons, tRNA has anticodons

mRNA is linear, tRNA is clover-shaped

mRNA has more than 3 coding bases, tRNA has 3 coding bases only

mRNA is a copy of the gene, tRNA carries an amino acid

Question 5

similarities between starch and glycogen

Answer 5

Both contain 1,4- and 1,6 – glycosidic bonds

Both polysaccharides

Both insoluble (don’t affect water potential of cells)

Both branched

Both alpha glucose

Question 6

differences between starch and glycogen

Answer 6

Starch made up of 2 polysaccharides – amylose and amylopectin; glycogen 1 polysaccharide

Glycogen more branched, as contains more frequent 1,6-glycosidic bonds than amylopectin

Glycogen more compact

Glycogen has more free ends for hydrolysis of glucose molecules

Glycogen – storage in animals, bacteria, fungi; starch – storage in plants

Question 7

similarities between starch and cellulose

Answer 7

Both polysaccharides
Both contain glucose monomers
Both found in plants
Both contain hydrogen bonds
Both insoluble

Question 8

differences between starch and cellulose

Answer 8

Starch made up of two different polysaccharides; cellulose molecules -> microfibrils -> macrofibrils]

Starch – alpha glucose; cellulose – beta glucose

Starch – contains branches (amylopectin) due to 1,6-glycosidic bonds; cellulose only contains 1,4-glycosidic bonds

Monomers in cellulose orientated 180º relative to next

Starch – storage; cellulose – cell walls

Question 9

similarities between DNA and RNA

Answer 9

Both contain adenine, cytosine, guanine
Both polynucleotides
Both contain pentose sugar
Both contain phosphate groups
Monomers joined by phosphodiester bonds

Question 10

differences between DNA and RNA

Answer 10

DNA – thymine; RNA - uracil

DNA – double stranded (double helix) and RNA – single stranded

DNA – deoxyribose; RNA - ribose

RNA shorter in length

Question 11

similarities between phospholipids and triglycerides

Answer 11

Both contain glycerol
Both contain fatty acids
Both contain ester bonds

Question 12

differences between phospholipids and triglycerides

Answer 12

Phospholipids are polar (due to phosphate head); triglycerides are non-polar

Phospholipids have 2 fatty acids, triglycerides have 3

Phospholipids have 2 ester bonds, triglycerides have 3

Phospholipids have a phosphate head

Question 13

similarities between chlorophyll and haemoglobin

Answer 13

Both contain ring structure
Both pigments
Both have methyl groups

Question 14

differences between chlorophyll and haemoglobin

Answer 14

Chlorophyll – porphyrin ring; haemoglobin has haem group

Chlorophyll – central magnesium ion;
haemoglobin – central iron ion

Haemoglobin is a protein; chlorophyll is not
Chlorophyll has different forms – a or b; haemoglobin only has 1 form

Chlorophyll absorbs sunlight; haemoglobin absorbs oxygen

Haemoglobin has quaternary structure (4 polypeptide chains); chlorophyll does not

Question 15

similarities between catalase and haemoglobin

Answer 15

Both proteins with quaternary structure (4 polypeptide chains)

Both contain four haem groups (with iron ion at centre)

Question 16

differences between catalase and haemoglobin

Answer 16

Catalase – 4 identical polypeptide chains; haemoglobin has 2 sets of 2 identical chains

Catalase has enzyme activity (digests hydrogen peroxide); haemoglobin binds oxygen molecules

Catalase found in lysosomes in phagocytes; haemoglobin found in red blood cells

Question 17

similarities between insulin and haemoglobin

Answer 17

Both proteins with quaternary structure
Both have disulfide bonds

Question 18

differences between insulin and haemoglobin

Answer 18

Insulin – 2 polypeptide chains; haemoglobin – 4 polypeptide chains

Haemoglobin contains iron ions, insulin does not

Insulin is a peptide hormone; haemoglobin is an oxygen absorbing pigment

Insulin binds to specific receptors; haemoglobin does not

Insulin produced by pancreatic beta cells; haemoglobin produced by red blood cells

Question 19

similarities between antibody and haemoglobin

Answer 19

Both proteins with quaternary structure
Both 4 polypeptide chains

Question 20

differences between antibody and haemoglobin

Answer 20

Antibodies have specific tertiary structure forming antibody binding site (in variable region); haemoglobin has tertiary structure relating to oxygen transport

Each polypeptide in haemoglobin contains haem group

Antibody quaternary structure stabilised by disulfide bonds; haemoglobin not

Antibodies bind antigens; haemoglobin binds oxygen