Introduction to genetic traits

Question 1

Where is DNA found?

Answer 1

In the nucleus

Question 2

What acid is present in DNA?

Answer 2

Nucleic acid?

Question 3

What is DNA?

Answer 3

molecule containing the genetic code of an organism, it determines inheritance (heredity)

Question 4

Describe DNA in different cells around the body

Answer 4

Almost every cell in the human body has the same DNA

Question 5

The DNA nucleotide is made up of what 3 parts?

Answer 5

5-carbon deoxyribose unit (a sugar)
phosphate group
nitrogenous base

Question 6

What 4 types of nucleotide subunit make up DNA?

Answer 6

Adenine (purine)
Thymine (pyrimidine)
Guanine (purine)
Cytosine (pyrimidine)

Question 7

DNA is composed of two what?

Answer 7

Complementary DNA strands made up of nucleotides

Question 8

The DNA strands are held together by what?

Answer 8

Hydrogen bonds between the nitrogenous bases of the nucleotides.

Question 9

What forms the DNA backbone?

Answer 9

Alternating deoxyribose and phosphate units

Question 10

How many H bonds bind A and T?

Answer 10

2

Question 11

How many H bonds bind G and C?

Answer 11

3

Question 12

The two DNA strands form what?

Answer 12

A double helix

Question 13

Describe down syndrome

Answer 13

aka trisomy 21
additional copy of chromosome 21
individuals have 47 chromosomes
Example of aneuploidy - anything other than diploid number of chromosomes
caused by errors in or failure of chromosomes to separate during meiosis = non-disjunction
characteristics: learning difficulties, distinctive physical features, congenital heart disease

Question 14

Klinefelter syndrome

Answer 14

XXY genotype
Characteristics: Long limbs, reduced testosterone, reduced fertility, learning difficulties

Question 15

Where are chromosomes found?

Answer 15

In the nucleus

Question 16

What are nucleosomes?

Answer 16

DNA wrapped around histones

Question 17

What forms fibres of chromatin?

Answer 17

Nucleosomes coiled together

Question 18

What forms chromosomes?

Answer 18

CHROMATIN FOLDED WITH THE HELP OF PROTEINS

Question 19

Why is DNA packaged?

Answer 19

Allows it to fit inside the nucleus and prevents damage during cell division

Question 20

What are the chromosomes 1-22

Answer 20

Autosomes

Question 21

What are chromosomes 23

Answer 21

Sex chromosomes

Question 22

What is a trait?

Answer 22

Specific characteristic of an organism

Question 23

What is the karyotype?

Answer 23

The particular collection of chromosomes an individual has

Question 24

What is each pair of autosomes referred to as?

Answer 24

Homologous chromosomes
They are the same size and contain comparable genes for the same characteristics
However, the genes may not be identical

Question 25

What is an allele?

Answer 25

Term used to describe different forms of the same gene

Question 26

What is genetics?

Answer 26

The study of genes and variation in the inheritance of traits

Question 27

What is inheritance?

Answer 27

Passing of traits from parents to offspring. Also known as heredity

Question 28

What are traits?

Answer 28

Specific characteristics of an organism Determined by interaction between genes and the environment

Question 29

What is a gene?

Answer 29

Section of DNA which when copied to mRNA codes for the production of a protein. DNA copied to mRNA via transcription mRNA gives rise to protein via process of translation.

Question 30

What is the central dogma of molecular biology?

Answer 30

States that genetic information flows in a specific direcion: DNA -> mRNA -> Proteins

Question 31

What are structural genes?

Answer 31

Code for proteins via transcription and translation

Question 32

What are regulatory genes?

Answer 32

Control for structural genes

Question 33

What is a mutation?

Answer 33

Any alteration to the structure of a gene some good, some bad produces genetic variation can cause ageing, disease mutations in germ cells can result in transmission of mutation to offspring

Question 34

Genotype

Answer 34

Genetic aspect contributing to a trait

Question 35

Phenotype

Answer 35

How traits appear as a result of interaction between genes and environment observable traits e.g. hair colour

Question 36

Alleles

Answer 36

Different forms of the same gene

Question 37

Locus

Answer 37

The particular (fixed) location of a gene on a chromosome

Question 38

Dominant

Answer 38

Demonstrated or takes precedence in the body and the phenotype

Question 39

Recessive

Answer 39

Alleles masked by dominant allele and are not displayed in phenotype

Question 40

Co-dominance

Answer 40

Both alleles of equal dominance e.g. AB blood group

Question 41

Autosomal dominant inheritance

Answer 41

Only one copy of mutated dominant allele needed to cause disease. Therefore not possible to be a carrier

Question 42

Autosomal recessive inheritance

Answer 42

Two copies of mutated recessive allele are required to cause disease X-linked recessive - linked to female X chromosmes

Question 43

Single gene inheritance

Answer 43

Gene altered by one nucleotide and this single nucleotide change alters one amino acid. aka single point genetic condition e.g. huntingtons disease

Question 44

Polygenic inheritance

Answer 44

Phenotype is a result of several genes Results in a wide range of phenotypic variation e.g. height, eye colour, hair colour, weight

Question 45

Multifactorial inheritance

Answer 45

Combined effect of more than one gene and environmental variables determine phenotype wide range of phenotypic variation e.g. skin, personality, inteligence e.g. alzheimers = genetic element + head injury e.g. asthma = genetic element + environmental triggers