bio revision 1 ch5

Question 1

franklin study

Answer 1

DNA is twisted into spiral or helix
nb are perpendicular
backnone is outside while nb is inside
more than 1 strand

Question 2

monomer to polymer is formed by:

Answer 2

peptidyl transferase enzyme

Question 3

watson and crick model

Answer 3

2 strands like a ladder antiparallel
ladder is sugar phosphate backbone and rungs are nitrogenous bases
rungs have the same width purines and pyrimidines
rungs consists of AT 2 H bonds and GC 3 H bonds
each turn consists of 10 pairs

Question 4

A T
are linked with

Answer 4

2 H bonds

Question 5

G C
are linked with

Answer 5

3 H bonds

Question 6

purines are:

Answer 6

الرجالة دايما بيور
AG 2 RINGS

Question 7

PYRIMIDINES ARE:

Answer 7

CT 1 RING

Question 8

what are the 2 chromosomal proteins?

Answer 8

histones and
non histones

Question 9

histones

Answer 9

structural
homogenous
has a positively charged they bind strongly to the negatively charged phosphate group at normal ph forming string of nucleotides
they are repeated as they have low molecular weight
they have high content of arginine and lysine that forms ionic bonds

shortens the DNA to a level (10 folds) that allows it to be replicated

Question 10

non histones

Answer 10

heterogenous
found in chromatin
are structural and regulatory
high molecular weight (low amount)

Question 11

structural non histones

Answer 11

has a role in spatial organization
forms packed proteins and condensed chromatins

Question 12

regulatory non histones

Answer 12

determine whether the DNA code will be used in making RNA, proteins and enzymes or not

Question 13

amoeba and yeast and E.coli are

Answer 13

eukaryotes
yeast and E.coli only have plasmids

Question 14

prokaryotes

Answer 14

unicellular only
single molecule of circular DNA
plasmids are present in some bacterial cells
not complicated with proteins
found in nucleoid
ha one point attached to the membrane
1.4 mm long
reproduce asexually only
not surrounded by a nuclear membrane

Question 15

eukaryotes

Answer 15

maybe unicellular or multicellular
full chromosomes
linear
plasmids are present in some yeast fungus only
complicated with proteins as histones and non histones
found in the nucleus
has many points of replicaion
2meters long
reproduce sexually or asexually

Question 16

chromatins has equal amounts of

Answer 16

DNA and proteins

Question 17

when the cell is at rest it is in the shape of

Answer 17

condensed chromatin

Question 18

chromosomes structure is clear in

Answer 18

eukaryotes during cell division

Question 19

length of DNA is

Answer 19

2 meters long

Question 20

what are the bearers of genetic information?

Answer 20

chromosomes

Question 21

griffith studied pneumonia and the results were:

Answer 21

discovered bacterial transformation
genetic material of the dead s strain has entered to the r strain and some mice died
did not know how it transfered

Question 22

avery and his colleagues

Answer 22

isolated the induced the bacterial transformation from the virulent bacteria
المادة اللي انتقلت للرررقيقة وقتلت الفيران
OBJECTION: DNA was contaminated with protein
مات مخنوق

Question 23

hershy and chase
(crucial experement)

Answer 23

radio active sulpher labelled the the protein coat of the phage: less than 3% of the viral protein entered the cell

radio active phosphorus labelled DNA: 100% DNA entered

Question 24

helicase function

Answer 24

بيكسر
breaks hydrogen bonds between the paired bases

Question 25

polymerase

Answer 25

adds nucleotides in the direction 5 to 3
h bonds are formed between the nitrogenous bases
covalent bonds is formed between the nucleotides sugar and the phosphate group

Question 26

ligase

Answer 26

join the gaps by forming covalent bonds (phosphodiester bonds) in the lagging strand

Question 27

what pathogens have the RNA genome?

Answer 27

HIV, influenza, corona, polio virus. hepatitis virus
high rate of mutation

Question 28

kleinfilter syndrome

Answer 28

XXY in men
false mutation as its not inherited

Question 29

turner syndrome

Answer 29

X in female
false mutation as its not inherited

Question 30

how did polyploidy happen?

Answer 30

non spontaneous desirable protein
non formation of spindelfibers that separates the chromosomes

Question 31

gene mutation

Answer 31

change in the gene sequence transferring it from dominant to recessive trait

Question 32

false mutation

Answer 32

happens in somatic cell
not transferred or inherited
somatic mutation

Question 32

true mutation

Answer 32

happens in gamete cells
inherited to the offspring
gamete mutation

Question 33

what are the structural proteins?

Answer 33

KFC

keratine: protective covering as skin acts as a 1st line of defence
fibrous proteins:actin and myosin
collagen: in any connnective tissue

histones and structural non histones proteins

Question 34

regulatory proteins

Answer 34

antibodies
enzymes
hormones (not steroidal)
blood proteins
regulatory non histones proteins

Question 35

adding colchicine or mustard gas or nitrous acid will lead to:

Answer 35

production of higher amount of auxins by killing the growing tip will lead to enlargement of the cells (polyploidy)

and higher auxins reach ovary and stimulates it to form seedless fruit

non separation of chromatins after centromere division

failure of membrane formation between 2 daughter cells