chapter 3😘😊

Question 1

5’ to 3’

Answer 1

The direction of synthesis on a nucleotide strand

Question 2

amino acid

Answer 2

An organic compound that is a building block within a polypeptide or protein

Question 3

Anticodon

Answer 3

A set of three consecutive nucleotides that is part of a tRNA molecule and is complementary to a codon; the three nucleotides consist of any of the four bases adenine, uracil, guanine or cytosine

Question 4

Apoptosis

Answer 4

A programmed series of events that leads to cell death (as a result of the dismantling of the internal contents of the cell by various enzymes, including caspases)

Question 5

Cellular machinery‘

Answer 5

Biological machines’ that work to manufacture a biological molecule; e.g. transcription machinery includes RNA polymerase and binding factors or proteins; the translation machine is the ribosome

Question 6

Chromosome

Answer 6

A structure composed of DNA and protein that contains linear arrays of genes carrying genetic information; prokaryotes generally have one circular chromosome, whereas eukaryotes have a number of linear chromosomes

Question 7

Coding DNA

Answer 7

The sections of DNA that code for a protein; they contain instructions that determine the order of the codons in the mRNA, which in turn determines the order of the amino acids in a polypeptide or protein

Question 8

Codon

Answer 8

A set of three consecutive nucleotides found in a DNA or an mRNA molecule; it carries codes for a specific amino acid; the three nucleotides consist of any of the four bases adenine, thymine, guanine and cytosine in the case of DNA, or adenine, uracil, guanine and cytosine in the case of mRNA

Question 9

Complementary base pairing

Answer 9

The phenomenon whereby guanine always hydrogen bonds with cytosine and adenine always hydrogen bonds with thymine; guanine and cytosine share three hydrogen bonds, and adenine and thymine share two hydrogen bonds; the complementary pairing enables the helical structure of DNA to form

Question 10

DNA (deoxyribonucleic acid)

Answer 10

The information-containing molecule present in all living things that contains the instructions, written in a chemical code, for the production of proteins by the cell; the information it contains is sufficient for the making and maintaining the organism; in addition, DNA is the genetic material that passes this information on to the next generation

Question 11

DNA helicase

Answer 11

An enzyme that helps the two strands of the DNA double helix unwind and separate

Question 12

DNA ligase

Answer 12

An enzyme used to catalyse the formation of a bond between two pieces of DNA

Question 13

DNA polymerase

Answer 13

A member of a class of enzymes found in all living things, that synthesises new strands of DNA based on a template strand and according to complementary base-pair rules; DNA polymerases are important tools in biotechnology because they are capable of making exact copies of fragments of DNA, enabling efficient and accurate amplification of DNA templates

Question 14

DNA replication

Answer 14

The process a DNA molecule undergoes to make a complete and identical copy of itself, readying a cell for cell division; it is a semi-conservative process, and the two daughter molecules contain exact copies of the genetic material in the parent molecule

Question 15

Double helix

Answer 15

The structure formed by double-stranded molecules of nucleic acids such as DNA; two linear strands that run opposite to each other and twist together

Question 16

enzyme

Answer 16

A reusable, biological catalyst that lowers the activation energy of a chemical reaction, making it proceed faster; it is a protein that is sensitive to factors such as temperature and pH

Question 17

gene

Answer 17

A unit of heredity that transmits information from one generation to the next; a segment of DNA that codes for a polypeptide

Question 18

Genetic code

Answer 18

The term used for the way that the four nitrogenous bases of DNA (adenine, thymine, guanine and cytosine) are ordered and contain information to direct the production of specific proteins

Question 19

Genome

Answer 19

All of the genetic material contained in an organism or a cell; it includes the sequence of the DNA in the chromosomes within the nucleus, mitochondria and chloroplasts

Question 20

Genome sequence

Answer 20

The sequence of consecutive DNA ‘letters’ spanning all the chromosomes of a cell from start to finish

Question 21

Genomics

Answer 21

The study of the genome – how genes interact with one another, the environment and the resultant proteins produced; knowledge of an organism’s entire DNA sequence

Question 22

Heredity

Answer 22

The study of inheritance, the genetic transmission of characteristics from one generation to another

Question 23

Lagging strand

Answer 23

The DNA strand that is synthesised discontinuously in small fragments, called Okazaki fragments, in a 5’ to 3’ direction

Question 24

Leading strand

Answer 24

The DNA strand that is synthesised continuously in a 5’ to 3’ direction

Question 25

Mature mRNA

Answer 25

mRNA that has been processed after transcription; non-coding introns have been removed and the remaining exons joined

Question 26

mRNA (messenger RNA)

Answer 26

The RNA molecule that carries the information from a gene to a ribosome for translation into a polypeptide; in eukaryotes it carries the message from the DNA in the nucleus out through a nuclear pore to a ribosome in the cytoplasm

Question 27

Nitrogenous base

Answer 27

A structural component of the nucleotides that make up DNA or RNA

Question 28

why 3’ to 5’ protein synthesis transcription

Answer 28

Nucleotides are always added to the 3’ end of the growing RNA molecule, so RNA polymerase must move in the opposite direction (3’ to 5’) along the DNA template.

Question 29

pre mrna

Answer 29

the initial RNA molecule synthesized directly from DNA during transcription.
It contains both:
Exons: Coding regions that will be expressed as part of the final protein.
Introns: Non-coding regions that are not involved in protein synthesis and need to be removed.

Question 30

anticodon trna part

Answer 30

A sequence of three bases that binds to the mRNA codon.