Week 7 Genetics

Question 1

How do scientists reference chromosomes?

Answer 1

For reference purposes, scientists have assigned numbers to the chromosomes using an order based on length.

Question 2

What is a recessive allele?

Answer 2

Two copies of the allele need to be present for the phenotype to be expressed.

• lower case

Question 3

How much heredity to children share with parents?

Answer 3

• Children get half their genetic material from each parent
• They have a 50% chance or 0.50 of sharing any particular gene with either parent

Question 4

What do genes do?

Answer 4

encodes the synthesis of a gene product, either RNA or protein.

• code for the production of proteins so that when that gene is activated the cell produces that specific protein
• found within the chromosomes
• carry the information that determines your traits, which are features or characteristics that are passed on to you — or inherited — from your parents.

Question 5

What is the difference between genotype and phenotype?

Answer 5

Question 6

What is Heredity?

Answer 6

the passage of characteristics from parent to offspring by way of genes

Question 7

What is an example of a phenotype where a single gene has only two alleles in humans?

Answer 7

ear wax has only 2 alleles

• either wet or dry
• can use punnett square for this

Question 8

What is the fundamental issue of human behaviour?

Answer 8

The fundamental issue of human behaviour is how the factors of genes and the environment interact to shape human behaviour

Question 9

What can be used to represent dominant versus recessive traits?

Answer 9

punnett square

Question 10

What are alleles?

Answer 10

different variants of a gene

• Alternative forms of a gene that produce different characteristics

Question 11

What is RNA?

Answer 11

similar to DNA, creating when genes are expressed

• Ribonucleic acid is a polymeric molecule essential in various biological roles in coding, decoding, regulation and expression of genes.

Question 12

What is the meaning of Mendelian genetics?

Answer 12

Proposes the idea of dominant and recessive traits

Question 13

What cells have only 23 chromosomes?

Answer 13

Except sex cells, which only contain 23 chromosomes

• two X chromosomes in females
• one X and one Y chromosome in males

Question 14

What are genes?

Answer 14

units of hereditary transmission (genetic blueprints)

• a basic unit of heredity and a sequence of nucleotides in DNA or RNA

Question 15

What are chromosomes?

Answer 15

strands of DNA wound around each other in a double-helix configuration and partly coated in protein

• with part or all of the genetic material of an organism. Most eukaryotic chromosomes include packaging proteins called histones which, aided by chaperone proteins, bind to and condense the DNA molecule to maintain its integrity.

Question 16

What are amino acids?

Answer 16

“building blocks of life”

• function as the building blocks (monomers) of proteins, which polymerize together and fold into a particular shape and will then perform a specific function

Question 17

Who coined Mendelian genetics?

Answer 17

Gregor Mendel in 1865 and 1866

Question 18

What is phenotype?

Answer 18

observable characteristics of a gene

• The term covers the organism’s morphology or physical form and structure, its developmental processes, its biochemical and physiological properties, its behavior, and the products of behavior.

Question 19

How much heredity do children share with grandparents?

Answer 19

• You have a 0.25 probability of sharing a particular gene with your grandparents
  
  • 0.50 x 0.50 or 0.25

Question 20

What are some examples of phenotypes?

Answer 20

• include height, wing length, and hair color.
• Phenotypes also include observable characteristics that can be measured in the laboratory, such as levels of hormones or blood cells.

Question 21

What is the human genome project?

Answer 21

an international scientific research project with the goal of determining the base pairs that make up human DNA, and of identifying and mapping all of the genes of the human genome from both a physical and a functional standpoint.

Question 22

How much heredity do children share with siblings?

Answer 22

Brothers and sisters also have a probability of 0.50 sharing the same gene with each other

Question 23

What are dizygotic twins?

Answer 23

fraternal

• two eggs (ova) are fertilised by two sperm and produce two genetically unique children.
• share 50% of genes

Question 24

How much heredity to children share with half siblings?

Answer 24

• It is also 0.25 probability for half siblings

Question 25

What is DNA?

Answer 25

(deoxyribonucleic acid): chemical substance containing nucleotides

Question 26

Describe the ladder of life

Answer 26

Question 27

what two alleles do humand receive for every gene?

Answer 27

• Homozygous
• Heterozygous

Question 28

What is an example of a disease where a single gene has only two alleles in humans?

Answer 28

Huntingtons disease

• Variation on a single gene with 2 alleles
• having the dominant leads to disease
  
  • changes in function of basal gingival which effect movement

Question 29

How many genes do human have?

Answer 29

~25000-35000

Question 30

What is epigenome?

Answer 30

Information about us stored outside of our DNA (tags that become attached to our DNA)

• An epigenome consists of a record of the chemical changes to the DNA and histone proteins of an organism;
• these changes can be passed down to an organism’s offspring via transgenerational stranded epigenetic inheritance

Question 31

What is a heterozygous gene?

Answer 31

a combination of alleles for a given genes

Question 32

What is a dominant allele?

Answer 32

In genetics, dominance is the phenomenon of one variant of a gene on a chromosome masking or overriding the effect of a different variant of the same gene on the other copy of the chromosome

• only need one copy
• upper case

Question 33

What is a polygenetic trait?

Answer 33

A polygenic trait is one whose phenotype is influenced by more than one gene

• Traits that display a continuous distribution,
• height or skin color
• Very few characteristics controlled by single gene with 2 alleles

Question 34

What is a genotype?

Answer 34

Specific genetic make-up of an individual

• A genotype is an organism’s complete set of genetic material.
• Often though, genotype is used to refer to a single gene or set of genes, such as the genotype for eye color. The genes take part in determining the characteristics that are observable in an organism, such as hair color, height, etc.

Question 35

How can genetics and epigenetics be compared to music?

Answer 35

• genetics = sheet music
• epigenetics = How music is played by the musician

Question 36

What shapes human behaviour?

Answer 36

nature and nurture

Both genes (nature) and the environment (nurture) interact to shape human behaviour

Question 37

What is epigenetic’s?

Answer 37

Above genetics

• Lasting changes in gene function caused by external or environmental factors without any change in the DNA itself
  
  • Activate or silence gene (turn “on” or “off”)
  • Alter how gene functions (gene expression)

Question 38

How many chromosomes are in humans?

Answer 38

23 pairs of chromosomes for a total of 46 in each cell of the body

Question 39

What are monozygotic twins

Answer 39

identical

• one fertilised egg (ovum) splits and develops into two babies with exactly the same genetic information
• share 100% of genes

Question 40

What is an example where a change in a single gene can lead to severe changes in development?

Answer 40

Phenylketonuria (PKU)

• Increased levels of phenylalanine,a building block of proteins
• Toxicity in neurons builds up and leadst o neuronal death
• Leads to a very severe changes in development:
  
  • Intellectualdisability
  • Delayeddevelopment
  • Behavioralproblems
  • Psychiatricdisorders

Question 41

What are some examples of alleles?

Answer 41

• APOE4 allele (effects hippocampus) is associated with an increased risk of Alzheimer’s disease

also:

• Attached earlobe or not
• Tongue rolling or not

Question 42

What is a genome?

Answer 42

complete set of genetic material for an organism

Question 43

What is the homozygous gene?

Answer 43

an identical pair of alleles for a given gene