Inheritance

Question 1

what are chromosomes

Answer 1

chromosomes are made of DNA, which contains genetic information in the form of genes

Question 2

what is a gene

Answer 2

a length of DNA that codes for a protein

Question 3

what is an allele

Answer 3

an alternative form of a gene

Question 4

Describe the inheritance of sex in humans

Answer 4

women have XX chromosomes
Men have XY chromosomes therefore men determine sex of a child

Question 5

what determines the sequence of amino acids

Answer 5

the sequence of bases in a gene determines the sequence of amino acids used to make a specific protein

Question 6

explain the different sequences of amino acids

Answer 6

the sequence of amino acids of a protein determines protein shape, since the chemical properties of each amino acid are forces that give rise to intermolecular interactions to begin to create secondary structures, such as a-helices and B- strands

Question 7

how does DNA control cell function

Answer 7

The DNA controls cell function by controlling the production of proteins, including enzymes, membrane carriers and receptors for neurotransmitters

Question 8

explain how a protein is made

Answer 8

1. the gene coding for the protein remains in the nucleus
2. messenger RNA (mRNA) is a copy of a gene
3. mRNA molecules are made in the nucleus and move to the cytoplasm
4. the mRNA passes through ribosomes
5. the ribosome assembles amino acids into protein molecules
6. the specific sequence of amino acids is determined by the sequence of bases in the mRNA

Question 9

Explain what most body cells in a n organism contain

Answer 9

the same genes, but many genes in a particular cell are not expressed because the cell only makes the specific proteins it needs

Question 10

what is a haploid nucleus

Answer 10

a nucleus containing a single set of chromosomes

Question 11

what is a diploid nucleus

Answer 11

a nucleus containing two sets of chromosomes. There are 23 pairs in a human diploid cell

Question 12

what is mitosis

Answer 12

nuclear division giving rise to genetically identical cells

Question 13

what is mitosis used for

Answer 13

mitosis is used in growth, repair of damaged tissues, replacement of cells and asexual reproduction

Question 14

what occurs before mitosis

Answer 14

Just before mitosis, each chromosome in the nucleus copies itself exactly. Chromosomes line up along the center of the cell where cell fibers pull them apart. The cell divides into two; each new cell has a copy of each of the chromosomes

Question 15

what are stem cells

Answer 15

unspecialized cells that divide by mitosis to produce daughter cells that can becomes specialized for specific functions

Question 16

what is meiosis

Answer 16

a reduction division in which the chromosome number is halved from diploid to haploid resulting in genetically different cells. Meiosis is involved in the production of gametes

Question 17

describe inheritance

Answer 17

the transmission of genetic information to generation

Question 18

describe genotype

Answer 18

the genetic make-up of an organism in terms of the alleles present

Question 19

describe phenotype

Answer 19

the observable features of an organism

Question 20

describe homozygous

Answer 20

having two identical alleles of a particular gene. two identical homozygous individuals that breed together will be pure- breeding

Question 21

describe heterozygous

Answer 21

having two different alleles of a particular gene. Heterozygous individual will not be pure- breeding

Question 22

describe a dominant allele

Answer 22

an allele that is expressed if it is present in the genotype

Question 23

describe a recessive allele

Answer 23

an allele that is only expressed when there is no dominant allele of the gene present in the genotype