Chapter 4: Genetics

Question 1

What are eukaryotes made of?

Answer 1

DNA and proteins

Question 2

Gene

Answer 2

a heritable factor that controls a specific characteristic

Question 3

Allele

Answer 3

one specific form of a gene, differing from other alleles by one or a few bases only and occupying the same gene locus as other alleles of the gene

Question 4

Genome

Answer 4

The whole of the genetic information of an organsom

Question 5

genemutation

Answer 5

a change to the base sequence of a gene

Question 6

What is meiosis for a kind of division?

Answer 6

Meiosis is a reduction division of a diploid (2n) nucleus to form a haploid (n) nucleus

Question 7

Homologous chromosomes

Answer 7

they have the same genes as each other, in the same sequence, but not necessarily the same alleles of those genes

Question 8

What is chrossing over

Answer 8

crossing over is the exchange of genetic material between non-sister chromatids

Question 9

Stages of Meiosis

Answer 9

prophase, metaphase, anaphase, telophase

Question 10

What is non-disjunction?

Answer 10

This occurs when the chromosomes do not separate properly during meiosis. This leads that the production of gametes have either to many or to few chromosomes. Zygotes that have to few chromosomes usually die, but the ones with too many survive. E.g. Down syndrom

Question 11

Karyotyping

Answer 11

chromosomes are arranged in pairs according to their size and structure

Question 12

How is karyotyping performed?

Answer 12

Itis performed using cells collected by chorionic villus sampling or amniocentesis, for pre-natal diagnosis of chromosome abnormalities

Question 13

Phenotype

Answer 13

the characteristics of an organism

Question 14

Dominant allele

Answer 14

an allele that has the same effect on the phenotype wether it is present in homozygous or heterozygous state

Question 15

Recessive allele

Answer 15

an allele that only has an effect on the phenotype when it is present in a homozygous state

Question 16

Locus

Answer 16

the particular position on a homologous chromosome of a gene

Question 17

Homozygous

Answer 17

having 2 identical alleles of a gene

Question 18

Heterozygous

Answer 18

having 2 different alleles of a gene

Question 19

Carrier

Answer 19

an individual that has one copy of a recessive allele that causes a genetic disease in individuals that are homozygous for this allele

Question 20

Test cross

Answer 20

testing a suspected homozygous and crossing it with a known homozygouse recessive

Question 21

Sex linkage

Answer 21

the assiciation of a characteristic with gender, because the gene controlling the characteristics is located on a sex chromosome

Question 22

What happens with the DNA in gel electrophoresis

Answer 22

fragments of DNA move in an electric field and are seperated according to their size (this method is used in DNA profiling)

Question 23

What happens with the amino acid sequence when genes are transfered between species

Answer 23

the amino acid sequence of polypeptides translated from them is unchanged because the genetic code is universal

Question 24

Clone

Answer 24

a group of genetically identical organsim or a group of cells derived from a single parent cell