Lecture 1 - introduction to genetics

Question 1

What is genetics the study of?

Answer 1

units of information (genes) and the way they are passed on (inheritance).

Question 2

What is heredity?

Answer 2

Offspring are similar to their parents

Question 3

What is variation?

Answer 3

Offspring are different from their parents and each other

Question 4

What is phenotype?

Answer 4

discernible properties of an individual

Question 5

What is genotype?

Answer 5

genetic information that influences those properties

Question 6

What are the 3 types of genetics?

Answer 6

• Molecular/developmental genetics
• Population/evolutionary genetics
• Transmission genetics

Question 7

What are molecular/developmental genetics?

Answer 7

transmitted from DNA to affect cell function & phenotypes

Question 8

What are population/evolutionary genetics?

Answer 8

transmitted over many generations within large populations

Question 9

What are transmission genetics?

Answer 9

transmitted from parent to offspring in families

Question 10

What principle demonstrated that DNA is the genetic material?

Answer 10

the transforming principle (Griffith) - genetic material can be moved between bacterial cells and change their properties

Question 11

What is the bacteriophage life cycle (Hershey & Chase)?

Answer 11

bacteriophage virus passed genetic material on

Question 12

What is the full name of DNA (which describes the structure of DNA)?

Answer 12

deoxyribonucleic acid

Question 13

Are animals, plants, fungi and protists multicellular or unicellular?

Answer 13

BOTH

Question 14

What are chromosomes made of?

Answer 14

chromatin = DNA + histones

Question 15

Why is DNA wrapped around highly conserved proteins called histones?

Answer 15

to form a compact structure

Question 16

What are the 4 parts of a linear chromosome?

Answer 16

• telomeres
• p arm
• q arm
• centromere

Question 17

What are telomeres?

Answer 17

repetitive sequences at each end of linear chromosomes that protect them from degradation

Question 18

What does the p arm stand for?

Answer 18

‘petite arm’ - shorter chromosome arm

Question 19

What does the q arm stand for?

Answer 19

‘letter after p’ - longer chromosome arm

Question 20

What is a centromere?

Answer 20

specialised region that acts as a site for the binding of kinetochore proteins - important in mitosis and meiosis

Question 21

What is the name given to genes found across the length of 2 chromosome arms at different positions?

Answer 21

loci (singular = locus)

Question 22

What are epigenetics?

Answer 22

reversible modification to chromatin structure can alter gene activity without changing the DNA

Question 23

What is euchromatin?

Answer 23

loosely packed chromatin that can be readily transcribed

Question 24

What is heterochromatin?

Answer 24

condensed structure that doesn’t allow expression genes in that region

Question 25

What controls the level of expression of genes?

Answer 25

it is controlled by addition of methyl and acetyl groups to the histone proteins

Question 26

What does DNA methylation lead to?

Answer 26

used to suppress the expression of genes

Question 27

What does histone acetylation lead to?

Answer 27

leads to relaxation of the chromatin and hence greater transcription

Question 28

What does it mean that epigenetics can be heritable?

Answer 28

it can have longer-term effects

Question 29

Does epigenetics change the DNA sequence?

Answer 29

NO - there are no changes to the DNA sequence

Question 30

What is a diploid?

Answer 30

2 homologous chromosomes with the same genes but different alleles

Question 31

What type of cell is a gamete?

Answer 31

Haploid - a single copy of each chromosome

Question 32

Are all eukaryotes diploid?

Answer 32

no

Question 33

What is a gene?

Answer 33

unit of hereditary information that occupies a fixed position (locus) on a chromosome

Question 34

What are alleles?

Answer 34

different versions of a gene

Question 35

How many nucleotides can alleles vary by?

Answer 35

alleles could differ by a single nucleotide, or by hundreds

Question 36

What is cytogenetics?

Answer 36

the study of chromosomes

Question 37

How can cytogenetics work?

Answer 37

by using a technique called G-banding: a chemical called Giemsa is used stain chromosomes - giving a unique banding pattern.

Question 38

What is a karyotype?

Answer 38

the chromosome complement of an individual

Question 39

What is the typical human karyotype?

Answer 39

- autosomes - 1-22 (paternal & maternal) - sex chromosomes - X & Y

Question 40

What is the sex chromosomes of females?

Answer 40

XX

Question 41

What is the sex chromosomes of males?

Answer 41

XY

Question 42

Where is most eukaryotic genetic material found?

Answer 42

nuclear chromosomes

Question 43

Where else is the DNA in a eukaryote, other than nuclear chromosomes?

Answer 43

mitochondria & chloroplasts

Question 44

Where do organelles originate from?

Answer 44

very ancient endosymbiotic events - bacterial-like genome

Question 45

Where are mitochondrial and chloroplasts DNA inherited from?

Answer 45

Cytoplasm - maternal inheritance (egg has large volume of cytoplasm, whereas this is negligible for sperm).