chapter 4

Question 1

chapter 3

what is Dna

Answer 1

there are 46 dna molecules in the nucleus of most human cells
made of polymers of nucleotides

called deoxyribonucleic acid

Question 2

chapter 3 lecture

what is a nucleotide

Answer 2

1 sugar, phosphate and nitrogneus base (this base can be qa pyrimidine or a purine (double rings)

Question 3

chapter 3 lecture

what are purines (double rings)

Answer 3

adenine, guanine

Question 4

chapter 3 lecture

what are pryimidines (single ring)

Answer 4

cytisine and thymine

Question 5

chapter 3 lecture

what is Dna structure

Answer 5

a double helix with phosphate groups alternating with sugar deoxyribose
the backbones are a pair of nigrogen bases

Question 6

chapter 3 lecture

what are nitrogenous bases united by?

Answer 6

they are united by hydrogen bonds in this manner
a to t( 2 hydrogen bonds) and c to g ( 3 hydrogen bonds)

purine to pyrimidine is referred to claw of complementary base pairing

Question 7

chapter 3 lecture

what are are genes

Answer 7

genetic instrucitons of synthesis of proteins

Question 8

chapter 3 lecture

what is a gene

Answer 8

a segment of dna that codes for specific protein

Question 9

chapter 3 lecture

what is a genome

Answer 9

all genese of 1 person from 25000-35000 genes
this is 2% of dna
98% is non coding dna ( plays a role in chromosome structure, regulation of gene activity, and junk dna)

Question 10

chromatin and chromosomes

what are chromatin?

Answer 10

fine filamentous dna material mixed with proteins (histones)
occurs as 46 long filaments called chromosomes
doubles when in cell division

Question 11

cell divison

what are sister chromatids

Answer 11

2 pair of parallel filamens identical in dna that get pulled apart to each daughter cell from the centromere. The pulling starts at the thr kinetochore on the centromere

Question 12

rna structure and function

what is Rna

Answer 12

there are the many types of rna’s
mRna, rRna (ribosomal), tRna
it has one nucleotide chain
uracil replaces thymin as nitrogenous base (in dna)
ribose replaces deoxyribose as sugar ( in dna)
interprets code dna code
instructions for protein synthesis
workins in cytoplasm

Question 13

gene

What is a gene

Answer 13

info containing segment that codes rna which makes protein

amino acid sequence of a protein is determined by nucleotide sequence in

Question 14

human genome

what is a genome

Answer 14

contains a 23 chromosome set which is 3.1 billion nucleotide pairs
in 23 chromosome set there are 46 human chromosomes
one set of 23 chromosomes came from each parent
each chromosome pair do not look alike but same genes

human genomoe project 1993-2003 identified 99% of human genome

Question 15

genetic code

how many amino acids are there

Answer 15

there are 20 amino acids from 4 nucleotides

Question 16

genetic code

what is genetic code?

Answer 16

system that makes 4 nucleotides code for amino acids sequence for all protein

Question 17

genetic code

what are base triplets?

Answer 17

3 dna nucleotide = 1 amino acid
codon=3 base sequence in mrna
64 possible codons= available for 20 amino acids but only 61 code for amino acids
other 3 codons are stop codons, uag,uga,uaa
start codon is AUG

Question 18

overview of protein synthesis

what cells have identical genes and do all genes active?

Answer 18

all body cells, except sex and some immune cells
no, only 1/3-2/3 of genes are used

Question 19

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what is mrna

Answer 19

a mirror image copy of the gene which migrates from nucleaus to cyoplasm and code reads for ribosome.

Question 20

overview of protein synthesis

what is rRNA