Variations And DNA

Question 1

What is the molecule that carries genetic information in cells?

Answer 1

DNA (Deoxyribonucleic Acid)

Question 2

Where is DNA found in eukaryotic cells?

Answer 2

In the nucleus, within chromosomes

Question 3

What is the structure that DNA is organized into within the nucleus?

Answer 3

Chromosomes

Question 4

How many chromosomes do humans typically have?

Answer 4

46 chromosomes (23 pairs)

Question 5

What is the name of the process where DNA makes a copy of itself?

Answer 5

DNA replication

Question 6

What are the four nitrogenous bases found in DNA?

Answer 6

Adenine, Thymine, Guanine, Cytosine

Question 7

What is the complementary base pair for Adenine in DNA?

Answer 7

Thymine

Question 8

What is the complementary base pair for Guanine in DNA?

Answer 8

Cytosine

Question 9

What is the name of the process where the genetic information in DNA is used to make proteins?

Answer 9

Protein synthesis (transcription and translation)

Question 10

What are chromosomes?

Answer 10

Tightly coiled DNA molecules which are found in the nucleus of a cell Chromosomes also carry a large number of genes.

Question 11

DNA

Answer 11

Is a composed chemical and it contains genetic material found in the nucleus of a cell. !!CONTAINS A CODE FOR AMINO ACIDS!!

Question 12

Amino acids

Answer 12

Molecules that combine to make proteins

Question 13

Gene

Answer 13

A section of DNA that codes for a specific protein. Genes tell the cell what order to put the amino acids in.

Question 14

Allele

Answer 14

Different versions of the same gene

Question 15

Karyotype

Answer 15

Chromosome map of an organism

Question 16

What is DNA made up of?

Answer 16

DNA is a polymer made up of many nucleotides.

Question 17

Why do long strands of DNA twist

Answer 17

To form a double helix

Question 18

What is a nucleotide

Answer 18

Nucleotides are organic molecules composed of a nitrogenous base, a sugar molecule and a phosphate group.

Question 19

How does DNA code for a protein

Answer 19

DNA strands consist of 4 different bases, in which 3 bases codes for 1 amino acid, so the bases to join together to form a protein. (Might be asked as a outline how this chain of dna leads to the production of haemogoblin)

Question 20

How is the helix held together

Answer 20

By hydrogen bonds between nitrogenous bases

Question 21

How do the nitrogenous bases bond

Answer 21

The base in one strand is joined to the base on the opposite strand in the helix

Question 22

Why are some parts of the DNA that are not coded?

Answer 22

There are parts of the DNA that don’t code for proteins. Since they switch genes on and off so these parts that are not coded control whether a gene is expressed or not, or if a protein was made.

Question 23

Describe the structure of a nucleotide (4marker)

Answer 23

Phosphates are attached to the sugar molecule, in which 1 of 4 bases are attached to the sugar molecule as well, nucleotides consist of A,T,C,G. The bases (nucleotides) in one strand join the bases in the opposite strand.

Question 24

Mutation-

Answer 24

An error in the sequence of DNA, occurs during cell division which produces a new allele.

Question 25

What does a gene do?

Answer 25

Controls different characteristics

Question 26

Why is DNA described as a polymer

Answer 26

Since it has many nucleotides

Question 27

How can variation cause differences between individuals/species

Answer 27

Due to the genes they have inherited. The conditions in which individuals have developed in (e.g. language) Combination of genes and environment

Question 28

What are the genetic factors of variation?

Answer 28

Meiosis forms non identical gametes (produces variation) Fertilization of both egg and sperm (DNA from both parents causes variation) Mutations (random change in the DNA sequence causes variation)

Question 29

What are the environmental factors of variation?

Answer 29

Race, ethnicity, nutrition

Question 30

How characteristics are passed down from Parents to offspring's?

Answer 30

Each parent has different alleles for specific traits. Alleles are passed down into gametes during meiosis. After fertilization, alleles from both parents unite in the zygote. Zygote divides into 2 forming identical cells each having a copy of alleles from both parents, by mitosis Dominant allele will express.

Question 31

The father of the twins has brown eyes. Explain how the characteristic of brown eyes has been passed from the father to both of his children. (4 Marks)

Answer 31

The father has the allele for brown eyes. Allele has been passed down into the fathers gamete cell, which has fertilized the egg, then the zygote divides by mitosis forming identical cells, each embryo will have the same alleles as the parents, and the dominant allele which is the fathers, will be expressed on the offspring.

Question 32

What is an enzyme?

Answer 32

Biological catalysts that speed up the rate of a reaction.

Question 33

Describe the structure of DNA-

Answer 33

DNA contains a double helix. Contains 4 different bases

Question 34

Explain how the sequence of bases in a DNA molecule codes for different proteins-

Answer 34

3 bases code for 1 amino acid. The sequence of bases in a DNA molecule determines the sequence of amino acids, and the sequence of amino acids determines which protein is being made

Question 35

What will happen if mutations or variation takes place in non coding DNA?

Answer 35

It will affect how genes will be expressed/ produce a different gene.