Life Goes On I

Question 1

Alleles:

Answer 1

Different forms of the same gene
E.g. Gene: seed type
Allele: round or wrinkly

Question 2

Asexual reproduction:

Answer 2

Reproduction does not require sex cells of another organisms. Hence all offspring are identical because there is no exchange of genetic material.

Question 3

Centomere:

Answer 3

Where the chromatids join together

Question 4

Chromatids:

Answer 4

Identical pieces of DNA (chromosome) held together by the centromere and pulled apart during cell division to make new identical chromosomes in newly- made cells.

Question 5

Chromatin:

Answer 5

Long thin fibres that packages DNA into smaller volume so it makes it easier to be used to give the code to make particular proteins

Question 6

Chromosomes:

Answer 6

Long coils of DNA and exist in pairs

Question 7

Diploid cells:

Answer 7

contains 2 of each type of chromosome. Thus 46 chromosomes in total. e.g. body cell

Question 8

DNA:

Answer 8

stores all coded information that determines physical appearance and body functions

Question 9

Dominant allele:

Answer 9

expressed in the phenotype of a heterozygous individual

Question 10

Gametes:

Answer 10

sex cells

Question 11

Genes:

Answer 11

Sections of DNA which contain a specific sequence of bases, instructions needed by cell to produce one protein

Question 12

Genetic code:

Answer 12

sequence of bases in a gene

Question 13

Genotype:

Answer 13

Specific combination of alleles, determine the phenotype

Question 14

Haploid cell

Answer 14

Contain only one type of chromosome e.g. sex cells

Question 15

Heterozygous:

Answer 15

where two alleles in the same gene are different

Question 16

Homozygous:

Answer 16

where the two allele for the same gene are the same

Question 17

Karyotypes:

Answer 17

Used to identify chromosomal abnormalities by extracting chromosomes from a cell, stained and photographed through a digital photograph

Question 18

Mitosis:

Answer 18

type of cell division that is involved in growth, development, repair of tissues and for eukaryotic organism’s sexual reproduction.
- process of replicating exact copies of body cells

Question 19

Mutagens:

Answer 19

environmental factors that increase the frequency of mutations. e.g. chemicals, radiation and UV

Question 20

Nucleotide:

Answer 20

The basic unit of the DNA and contains sugar, phosphate group and a nitrogenous base

Question 21

Phenotype:

Answer 21

appearance of an organism

Question 22

Recessive allele:

Answer 22

allele whose effect remains hidden

Question 23

Meiosis:

Answer 23

process where diploid cells are converted into haploid gametes in gonads of multi-cellular sexually producing organism

Question 24

Sexual reproduction:

Answer 24

Union of two cells (fertilisation), combination of two gametes in an organism causing genetic
During sexual reproduction, each parent provides one set of chromosome

Question 25

What are the phases of mitosis?

Answer 25

Prophase: The chromosomes condenses and miotic spindles begin to capture and organise the chromosomes. Metaphase: The spindles has captured the chromosomes and lined them up at the middle of the cell. Anaphase : Sister chromatids separate from each other and are pulled towards opposite ends of the cell. Telophase: the cell is nearly done dividing, and it starts to re-establish its normal structures as cytokinesis (division of the cell contents) takes place. The mitotic spindle is broken down into its building blocks. Two new nuclei form, one for each set of chromosomes. Nuclear membranes and nucleoli reappear. The chromosomes begin to decondense and return to their “stringy” form. Interphase: