3.14 - Inheritance part 1

Question 1

What is a genome?

Answer 1

The entire set of the genetic material of an organism

Question 2

What do genes contain?

Answer 2

Each gene within the genome is made up of a small section of DNA that codes for a particular sequence of amino acids. Different sequences of amino acids form different proteins

Question 3

What are Alleles?

Answer 3

different versions of the same gene

Question 4

What is it called for having 2 types of the same alleles?

Answer 4

homozygous

Question 5

What is it called having 2 alleles that are different ?

Answer 5

heterozygous

Question 6

What do genes do?

Answer 6

Genes control our characteristics as the code for proteins which play important roles in cell activity

Question 7

Where are chromosomes found and formed

Answer 7

In the nucleus of a cell, the DNA double helix supercoils to form the structures of chromosomes

Question 8

How many Chromosomes does a human body cell contain

Answer 8

23 pairs of chromosomes. One Chromosome from a pair is inherited from each parent. Each Chromosome pair is called a homologous pair.

Question 9

What are the 23rd pair of chromosomes in the cell

Answer 9

The 23rd pair of Chromosomes are the sex chromosomes.
In females, the sex chromosomes are the same homozygous genotype (XX)
In males the sex chromosomes are different a heterozygous genotype (XY)

Question 10

How many Chromosomes do Gametes contain

Answer 10

23 individual chromosomes. This is half the full number of a body cell and call the halploid number.

Question 11

What is the structure of DNA?

Answer 11

DNA is a polymer made up of two strands coiled around to make a double helix. The strands are formed from a sugar phosphate backbone with bases joined together by complementary base pairing
Adenine pairs with thymine
Guanine pairs with cytosine

Question 12

What is the structure of RNA

Answer 12

RNA is a polynucleotide- it is made up of many nucleotides linked together in a long chain. RNA nucleotides contain the nitrogenous bases adenine (A), guanine (G) and cytosine (C).
Each RNA polynucleotide strand is made up of alternating ribose sugars and phosphate groups linked together, with the nitrogenous bases of each nucleotide projecting out sideways from the single-stranded RNA molecule
. A codon is a base triplet found on DNA or mRNA that codes for one amino acid. An anticodon is a base triplet found on tRNA that is complementary to a codon.

Question 13

What are the differences between DNA and RNA

Answer 13

Unlike DNA, RNA nucleotides never contain the nitrogenous base thymine (T) – in place of this they contain the nitrogenous base uracil (U)
Unlike DNA, RNA molecules are only made up of one polynucleotide strand (they are single-stranded

Question 14

What is the structure
of a gene

Answer 14

a sequence of nucleotide bases in a DNA molecule that codes for the production of a specific sequence of amino acids that in turn make a specific polypeptide

Question 15

What are the two stages of protein synthesis

Answer 15

Transcription – DNA is transcribed and an mRNA molecule is produced
Translation – mRNA (messenger RNA) is translated and an amino acid sequence (protein) is produce

Question 16

What is the process of Transcription

Answer 16

This stage of protein synthesis occurs in the nucleus of the cell
Part of a DNA molecule unwinds (the hydrogen bonds between the complementary base pairs break)
This exposes the gene to be transcribed (the gene from which a particular polypeptide will be produced)
A complementary copy of the code from the gene is made by building a single-stranded nucleic acid molecule known as mRNA (messenger RNA)
The mRNA molecule leaves the nucleus via a pore in the nuclear envelope

Question 17

What is the process of Translation

Answer 17

This stage of protein synthesis occurs in the cytoplasm of the cell
After leaving the nucleus, the mRNA molecule attaches to a ribosome
In the cytoplasm, there are free molecules of tRNA (transfer RNA)
These tRNA molecules have a triplet of unpaired bases at one end (known as the anticodon) and a region where a specific amino acid can attach at the other
There are at least 20 different tRNA molecules, each with a specific anticodon and specific amino acid binding site
The tRNA molecules bind with their specific amino acids (also in the cytoplasm) and bring them to the mRNA molecule on the ribosome
The triplet of bases (anticodon) on each tRNA molecule pairs with a complementary triplet (codon) on the mRNA molecule
Two tRNA molecules fit onto the ribosome at any one time, bringing the amino acid they are each carrying side by side
A peptide bond is then formed between the two amino acids
This process continues until a ‘stop’ codon on the mRNA molecule is reached – this acts as a signal for translation to stop and at this point the amino acid chain coded for by the mRNA molecule is complete
This amino acid chain then forms the final polypeptide (protein)

Question 18

What is gene

Answer 18

A gene is a short length of DNA found on a chromosome that codes for a particular characteristic (expressed by the formation of different proteins)

Question 19

What are alleles

Answer 19

Alleles are variations of the same gene
As we have two copies of each chromosome, we have two copies of each gene and therefore two alleles for each gene
One of the alleles is inherited from the mother and the other from the father
This means that the alleles do not have to ‘say’ the same thing

Question 20

What is a dominant allele

Answer 20

A dominant allele is always expressed even if only one copy is present

Question 21

What is a recessive allele

Answer 21

A recessive allele is only expressed if two copies are present ( no dominant allele)

Question 22

What is a genotype

Answer 22

The combination of alleles that control each characteristics

Question 23

What is a phenotype

Answer 23

The observable characteristics of an organs

Question 24

What is Codominance

Answer 24

Both alleles within a genotype are expressed in the phenotype of an individual

Question 25

What is an example of codominance

Answer 25

Inheritance of blood group.

Question 26

Who is responsible for the Sex determination of a child

Answer 26

Sex is determined by an entire chromosome pair. Females have the sex chromosomes XX
Males have the sex chromosomes XY
As only a father can pass on a Y chromosome, he is responsible for determining the sex of the child

Question 27

What does polygenic mean

Answer 27

Characteristics that are controlled by more than one gene are polygenic

Question 28

What is polygenic inheritance

Answer 28

The inheritance of polygenic characteristics

Question 29

What are Monohybrid inheritance

Answer 29

Inheritance of characteristics controlled by a single gene

Question 30

What diagram can show all the possible combinations of alleles

Answer 30

a punnet square

Question 31

What is RNA?

Answer 31

RNA is a single stranded molecule of genetic information. The base of uracil

Question 32

What is a carrier?

Answer 32

Someone with a heterozygous genotype that can pass on diseases

Question 33

What DNA bases pair with each other?

Answer 33

Adenine pairs with thymine
Guanine pairs with cytosine

Question 34

What is DNA?

Answer 34

Molecule with a code on it that codes for a sequence of amino acids and therefore characteristics

Question 35

What is a family pedigree?

Answer 35

A family tree of genetic disorders.

Question 36

How can doctors detect a genetic disease?

Answer 36

Look for symptoms
look at family history
do a genetic test

Question 37

how can a disease be caused by a recessive allele?

Answer 37

Conditions is present in the offspring but no parents
condition skips generation.

Question 38

What do all the letters translate too?

Answer 38

T-A
A-U
C-G
G-C