Lecture 11- Genetics

Question 1

What is studying genetics?

Answer 1

Considered to be the study of heredity such as study of how traits are passed from generation to generation

Question 2

What is the dominant Allele?

Answer 2

An allele that is expressed in the phenotype when when only one copy is present

Question 3

What is recessive allele?

Answer 3

An allele that is only expressed when two copies are present in the genotype.

Question 4

What did Mendel discover to help him be identified as the first geneticist?

Answer 4

Part of findings found that peas get one version of each trait from each parent (allele)and that some seemed to be dominant whilst others were recessive.

Question 5

What did Mendel discover about expression of dominant traits?

Answer 5

Dominant traits are expressed in an organism’s phenotype

Question 6

What did Mendel discover about expression of recessive traits?

Answer 6

Recessive traits are only expressed in absence of dominant trait.

Question 7

What does Mendelian inheritance suggest?

Answer 7

Phenotype traits will depend on your parents, as you receive an allele of each gene from each.

eg dimples are dominant but even if both parents have dominant and recessive, the proportion will be 3:1.

Question 8

What are the 2 fundamental laws of the Mendelian inheritance?

Answer 8

Segregation
Independence

Question 9

What is Segregation regarding mendelian inheritance?

Answer 9

Traits are either dominant or recessive

Question 10

What is Independence regarding Mendelian inheritance?

Answer 10

Varieties of each trait sort independently of each other

Question 11

What was discovered in current research due to being able to look closer than Mendel?

Answer 11

Deoxyribonucleic acid (DNA) can be found in the nucleus of every cell of an organism. It is composed of two chains of nucleotides that coil around each other to form a double helix.

Question 12

What are the 4 nucleotides?

Answer 12

A= Adenine T= Thymine G= Guanine C= Cytosine

Question 13

What goes with Adenine (A) in the chains?

Answer 13

Goes with Thymine (T)

Question 14

What goes with Guanine (G) in the chains?

Answer 14

Cytosine (C)

Question 15

What does the DNA double helix contain?

Answer 15

This double helix contains the genetic instructions for the development, functioning, growth and reproduction of all known biological organisms.
This means that the entire DNA of a being can be found in each individual cell.

Question 16

What is the process of translation in DNA?

Answer 16

The strands are “unzipped” and read by ribonucleic acid (RNA) molecules to produce protein strands.

Question 17

What occurs in the process of DNA to chromosomes?

Answer 17

-When in a cell’s nucleus, these long strands of DNA are called chromatids and are usually tangled together when a cell is active.

-When a cell needs to divide (mitosis), chromatids undergo condensation (the act of coiling tight like a spring to form a chromosome).

Question 18

What happens during chromosomes to genome?

Answer 18

• Typical humans have 46 chromosomes (23 pairs). All pairs are XX, aside from the final pair which may vary. This pair codes for biological sex, with biological females having XX and males having XX - Individual sequences of DNA on these chromosomes are called genes, with humans possessing between 20,000 to 25,000 genes. The aggregate of these genes is called a genome.

Question 19

What happens within genes?

Answer 19

-Some phenotype traits may be programmed by a single gene (pleiotropic), while others may be influenced by a combination of genes (polygenic).
Eg gene that codes for ear wax is on chromosome 16 (locus). This gene has two versions (alleles); a dominant version for wet ear wax and a recessive version for dry ear wax.

Question 20

What are the 3 suggestions that challenge the idea of Mendel’s laws?

Answer 20

X-linked conditions
Sporadic mutations
Polygenic traits

Question 21

What are X-linked conditions?

Answer 21

Some recessive traits are more prevalently expressed in males when compared to females. This is because they may not have a dominant allele on their (much shorter) Y chromosome

Question 22

What are some examples of x-linked conditions?

Answer 22

Colorblindness= First reported case of human X linkage
Turner syndrome= Affects females, X partially missing, 1/2,500
Triple X syndrome= Individuals with three X chromosomes, typically assigned female at birth. Most have no severe physical differences but may have a slightly taller height and an increased risk of mild developmental and learning challenges.

Question 23

What are Sporadic mutations?

Answer 23

Caused by errors or interference in typical cell division. These mutations can happen naturally or be the result of environmental factors

Question 24

What are 2 examples of Sporadic mutations?

Answer 24

-Down syndrome, affects 1/1000, due to trisomy (extra version) of chromosome 21, symptoms incl facial dysmorphology -Williams syndrome, affects 1/18,000, due to micro deletion on chromosome 7, symptoms include facial dysmorphology

Question 25

What are Polygenic traits?

Answer 25

These conditions or disorders reply on coding from multiple genes and may not consistently follow Mendelian rules. Eg SZ, affects 20M worldwide, individuals are considered to be genetically predisposed to develop schizophrenia, suggesting a clear genetic basis.

Question 26

What are genomic studies?

Answer 26

Inspects the genome of specific groups, identifies allele commonalities eg studying an extended family prone to Huntington’s helped identify the genetic markers

Question 27

What are targeted mutations?

Answer 27

Mutated lab produced genes are inserted into chromosomes w/ 2 types: -Defective and failing to produce specific functional protein -Produce new or different proteins

Question 28

What is genetic engineering?

Answer 28

-Technology such as CRISPR allow us to directly edit our own genome -Currently being used to tackle diseases such as HIV, cancer

Question 29

What is the definition of genotype?

Answer 29

The genetic makeup of a biological organism

Question 30

What is the definition of phenotype?

Answer 30

Observable characteristics of a biological organism. Can be physical or behavioural

Question 31

What is the definition of heredity?

Answer 31

Passing of physical and mental characteristics from one generation to another

Question 32

What is the definition of DNA?

Answer 32

Self replicating material found in nearly all living organisms, carrier of genetic information used to instruct formation of proteins

Question 33

What is the definition of RNA?

Answer 33

A messenger that carries instructions from DNA

Question 34

What is the definition of translation?

Answer 34

The act of turning genetic information found in DNA into proteins

Question 35

What is the definition of a chromatid?

Answer 35

Long strands of DNA found in the nucleus of active cells

Question 36

What is a chromosome?

Answer 36

Long DNA molecule with part or all of the genetic info of an organism.

Question 37

What is the definition of a gene?

Answer 37

Single strand of functional DNA on a chromosome.

Question 38

What is the definition of a genome?

Answer 38

A collection of genes

Question 39

What is a locus?

Answer 39

Term to describe a single strand of functional DNA on a chromosome

Question 40

What is an Allele?

Answer 40

Term used to describe different version of a gene and can be dominant or recessive

Question 41

What is the definition of Pleiotropic?

Answer 41

Traits that are coded by a single gene within a genome

Question 42

What is the definition of Polygenic?

Answer 42

Complex traits that are coded by multiple genes within a genome