toTopic 5 Assignment
DNA: Deoxyribonucleic acid
Vocabulary:
DNA- the set of non-genetic traits, qualities, or features that characterize a person or thing
Chromosomes- any of several threadlike bodies, consisting of chromatin, that carry the genes in a linear
order: the human species has 23 pairs, designated 1 to 22 in order of decreasing size and X and Y for the
female and male sex chromosomes respectively.
Adenine- one of the fundamental components of nucleic acids, as DNA, in which it forms a base pair with
thymine, and RNA, in which it pairs with uracil.
Guanine- a fundamental constituent of DNA and RNA, in which it forms base pairs with cytosine.
Cytosine- that is one of the fundamental components of DNA and RNA, in which it forms a base pair with
guanine.
Thymine- one of the principal components of DNA, in which it is paired with adenine.
Gene- the basic physical unit of heredity; a linear sequence of nucleotides along a segment of DNA that
provides the coded instructions for synthesis of RNA, which, when translated into protein, leads to the
expression of hereditary character.
Allele- any of several forms of a gene, usually arising through mutation, that are responsible for
hereditary variation.
Somatic Cells- one of the cells that take part in the formation of the body, becoming differentiated into
the various tissues, organs, etc.
Mitosis- the usual method of cell division, characterized typically by the resolving of the chromatin of the
nucleus into a threadlike form, which condenses into chromosomes, each of which separates
longitudinally into two parts, one part of each chromosome being retained in each of two new cells
resulting from the original cell.
Meiosis- part of the process of gamete formation, consisting of chromosome conjugation and two cell
divisions, in the course of which the diploid chromosome number becomes reduced to the haploid.
Compare mitosis.
Genetic Engineering
Biotechnology- the use of living organisms or other biological systems in the manufacture of drugs or
other products or for environmental management, as in waste recycling: includes the use of bioreactors in
manufacturing, microorganisms to degrade oil slicks or organic waste, genetically engineered bacteria to
produce human hormones, and monoclonal antibodies to identify antigens.
Transgenic- of, pertaining to, or containing a gene or genes transferred from another species
Dominant Trait- a trait that will appear in the offspring if one of the parents contributes it.
Recessive Trait- a trait that must be contributed by both parents in order to appear in the offspring.
Incomplete Dominance- the appearance in a heterozygote of a trait that is intermediate
between either of the trait's homozygous phenotypes.
1. Outline how DNA was discovered.
James Watson and Francis Crick discovered it
2. Draw and label the chemical structure of DNA that was modeled by
James Watson and Francis Crick.
Double Helix
3. What is the genetic code?
A genetic code is the specific sequence of genes aligned in different
chromosomes in the nucleus of a cell.
4. What enables DNA to have so many variations with only 4 chemicals?
There are so many different combinations.
5. Different human cells (somatic cells) have different life spans – fill in the
Table.
Somatic Cells
Life Span
Brain cells
30-50 years
Red blood cells
120 days
Stomach lining cells
2 days
Liver cells
200 days
Intestine lining cells
3 days
Skin cells
20 days
6. Explain the detailed process this illustration demonstrates
A sperm and egg go together to make an embryo, which turns into a fetus and becomes
a baby.
7. Some organisms can reproduce sexually and asexually. Explain the
Advantages and disadvantages of each process.
Reproduction
Advantages
Disadvantages
Sexual
More variation in genes
It takes a lot of energy
Asexual
You can reproduce faster
Doesn’t have any variation
8. Explain how biotechnology can increase or decrease variation.
Scientists can change the specific genes in the organisms
9. Describe a positive effect of biotechnology.
You can make foods better and plants with fatter foods
10. Describe a negative consequence of biotechnology.
We don’t know what it will do to the environment.