Genetics

Question 1

what is a centromere and the 4 major types

Answer 1

• metacentric- middle
• submetacentric- centromere toward one end
• Acrocentric- very close to end
  -Telocentric- very tip of arms

Question 2

gene

Answer 2

hereditary units that control particular characteristics/ traits

Question 3

genotype vs phenotype

Answer 3

phenotype- The trait that is expressed. E.g. Bb but have black hair appearance
genotype- the pair of alleles E.g Bb

Question 4

allele

Answer 4

different form of gene represented via symbols

Question 5

Types of chromosomes

Answer 5

• Autosomes (somatic) (1-22)
• Allosomes (gametes) (23)

Question 6

Ploidy

Answer 6

number of chromosome sets that a cell carries
- haploid ( half)
- diploid

Question 7

Homologous chrom vs non homologous chrom

Answer 7

homologus- identical pairs of chromosomes
- carry the same genes but not the same versions of gene e.g mum and dad one brown and one blonde
- non homologus- different chromosomes that carry different genes

Question 8

Karyotype

Answer 8

visual representation of chrom

Question 9

what are chromosomes counted by

Answer 9

centromere

Question 10

Meiosis

Answer 10

only occurs in eukaryotes
allows for genetic variability vis genetic recombination and crossing over
- is a reduction division resulting in 4 haploid daughter cells

Question 11

genetic variations in gametes

Answer 11

• random crossing over during prophase 1
  > genes from non-sister chromatids are swapped
  > creates gametes with unique chrom
• Independent assortment during metaphase 1
  > homologus chroms line up @ equator RANDOMLY

Question 12

what is a loci/locus

Answer 12

the specific location of a gene on a chromosome

Question 13

what does DNA stand for

Answer 13

Deoxyribonucleic acid

Question 14

DNA definition

Answer 14

• is a complex molecule that contains all the genetic info necessary to build and maintain an organism

Question 15

what are the nitrogenous base for DNA and RNA

Answer 15

DNA- ATGC
RNA- AUGC
- cytosine, adenine, guanine, thymine

Question 16

DNA structure

Answer 16

-sugar phosphate backbone
- DNA is made up of building blocks called nucleotides
- DNA is coiled around histones( protein that provides structural support)

Question 17

structure

Answer 17

Bases > Nucleotide > DNA > Nucleosomes > Chromosomes

Question 18

nucleotide structure

Answer 18

• purines- double ring DNA structure
• Pyramidines- single ring

Question 19

DNA vs RNA

Answer 19

r- single stranded DNA
- diff nitrogenis base Uracil replaces thymine
- present during DNA rep
d- two strands anti parrelel
5’-3’, 3’-5’

Question 20

impacts on Phenotypes

Answer 20

• genotypes and environmental influence

Question 21

enviro influence

Answer 21

The environment can change gene expression and therefore the phenotype.

Question 22

Epigenetics

Answer 22

• The study of how the environment changes gene expression (how the environment changes the phenotype)

Question 23

Types of phenotypes

Answer 23

co dominance
> both alleles are equally expressed
e.g r,w, roan cow (rw)
incomplete dominance
> become blend e.g r ,w , pink

Question 24

chaisma

Answer 24

point of crossing over on a chrom

Question 25

define recombination

Answer 25

The crossing over of chromosomes during Prophase - chromosomes swap alleles to create recombinant gametes

Question 26

define monosomy

Answer 26

having on less chrom (45)

Question 27

define gene linkage

Question 28

pedigree patterns

Answer 28

x linked dom - x linked recessive - autosomal dom- two affected parents with not all children affected autosomal recessive- two unaffected parents w affected child

Question 29

crossing over

Answer 29

during first division in meiosis. Produces chromosomes with new combos of genetic info

Question 30

recombinant chromatids

Answer 30

after crossing over where some of the chromosomes have new combos of gene (mum and dad)

Question 31

meiotic cell division

Answer 31

1. Interphase before meiosis occurs DNA is replicated, chromosomes duplicate, result in two identical sister chroms 2. P1- condens, plump and visible 3. M1- line up in the middle (equator), arranged independently(indep assortment), spindle fibres attach to centromere 4. A1- spindles shorten and pull the chroms apart 5. T1Cleavage furrow is formed as two separate nuclei form 6 cytokinesis 1 2 haploid daughter cells 7. P2 SPINDLE FIBRES ARE RECREATED 8. duplicated chroms line up in middle, spindle fibres attach to centromere 9. A2 spindles shorten separating sister chromatids 10. T2 cleavage furrow formed 11. 4 haploid daughter cells

Question 32

trisomy

Answer 32

additional chrom (47)

Question 33

trisomy 21

Answer 33

down syndrome -flat face, short neck, tonge tends to stick out

Question 34

trisomy 13

Answer 34

patau syndrome - intellectual disability, cleft lip/palate

Question 35

trisomy 23

Answer 35

k linefelter syndrome - male carries 2 X chroms (XXY) -tall, shorter torso, absent/ delayed puberty

Question 36

monosomy 23

Answer 36

- female only carries one x - short, infertile