Chapter 6 DNA structure

Question 1

Name the place where DNA is located in a eukaryotic cell.

Answer 1

Nucleus, chloroplasts, mitochondria

Question 2

Identify the components of a chromosome from a eukaryotic cell.

Answer 2

DNA double helix and histone proteins

Question 3

Explain homologous.

Answer 3

A pair of chromosomes that have the same size, shape and genes at the same locations

Question 4

Explain sister chromatid.

Answer 4

One of the two identical copies of a single chromosome, formed by replication and connected by a centromere

Question 5

Describe the DNA in the mitochondria and chloroplasts of eukaryotic cells.

Answer 5

Is similar to the single, circular chromosomes in prokaryotic cells.

Question 6

Explain what a karyotype is.

Answer 6

It displays the number and structure of chromosomes at cell division - metaphase.

Question 7

what is metaphase

Answer 7

Happens during cell division

Question 8

what is a gene

Answer 8

region/s of DNA that are made up of nucleotides
-Unit of heredity
-transmits information from one generation to the next

Question 9

Explain RNA replication.

Answer 9

-Single stranded
-Has uracil in place of thymine
-Has ribose sugar instead of deoxyribose sugar
-Functions as a structural part of ribosomes and in protein synthesis

Question 10

Leading strand of DNA

Answer 10

made continuously

Question 11

Lagging strand of DNA

Answer 11

Made in fragments

Question 12

Plasmids

Answer 12

Small circular piece of DNA found in bacteria which can replicate independently of the cells chromosomes.
-often contains antibiotic resistant genes.

Question 13

The type of chemical bond that holds strands of DNA together

Answer 13

Hydrogen bonds between complementary nitrogenous bases

Question 14

pathogenic

Answer 14

causes disease, bacteria

Question 15

Function and structure of a gene

Answer 15

-Codes for a polypeptide, segment of DNA
-Unit of heredity, transmits information from one generation to the next

Question 16

Genome

Answer 16

-All genetic material in an organism or cell
-bigger than gene
-In eukaryotes includes DNA in mitochondria and chloroplasts and chromosomes in nucleus

Question 17

DNA replication process

Answer 17

Double helix seperates into two individual strands. Results in two double strands of DNA identical to the original molecule

Question 18

Replication fork

Answer 18

Between unwound single strands of DNA and the intact double helix,
-between DNA helicase and DNA polymerase

Question 19

DNA

Answer 19

double stranded molecule that occurs bound to proteins (histones) in chromosomes in the nucleus

Question 20

DNA replication

Answer 20

process by which DNA makes a copy of itself during cell division

Question 21

Process of DNA replication: DNA polymerase

Answer 21

DNA polymerase joins free nucleotides to the growing new complementary strand

Question 22

Process of DNA replication: Helicase

Answer 22

DNA helicase unzips the double stranded DNA (parental strand) by breaking weak hydrogen bonds between nucleotides

Question 23

Structure of DNA

Answer 23

Nucleotides are composed of:
1. 5 carbon sugar
2. negatively charged phosphate group
3. A base - an organic nitrogen

Question 24

DNA in prokaryotes

Answer 24

DNA is single and circular, lies in direct contact with the cytoplasm

Question 25

DNA in eukaryotes

Answer 25

DNA found in the membrane bound nucleus, chloroplasts and mitochondria

Question 26

5’ to 3’ DNA replication

Answer 26

DNA is only synthesised in the 5’ to 3’ direction

Question 27

Chromatin and its structure

Answer 27

Complex of proteins and DNA in eukaryotic chromosomes

-Structure: chromosomes are single, long double helix coiled around histones unless cell is actively dividing

Question 28

Chromosomes and its structure

Answer 28

-X shaped
-Have undergone replication in readiness for cell division

-Structure: Composed of DNA, linear arrays in eukaryotes