1. Distinguish between saturated and unsaturated fats and between cis and trans fat molecules.
Saturated Fats
Unsaturated Fats
Solid at room temperature
Liquid at room temperature
Contain no double bonds in chemical structures
Contain one or more double bonds in chemical
structures
“Saturated” with hydrogen
Fewer hydrogen atoms on their carbon chains
Unhealthy fats because they can increase cholesterol
Healthier fats because they can help lower
levels: the bad cholesterol is the factor of heart disease cholesterol levels.
Animal meat: beef, poultry, pork
Nuts, Olives, Avocados
Dairy product: cheese, milk, butter
Plant oils: canola, vegetable, plant oil
Processed meats: sausages, hot dogs, bacon
Certain fish: salmon, tuna, anchovy, and others
Pre-packaged snacks: cookies, chips, crackers
containing omega-3 fatty acids
Cis Fats
Trans Fats
Health effect
Good for heath
Appearance
Occur naturally
Arrangement of
atoms
The chains of carbon atoms are on the
same side of the double bond,
resulting in a kink
Low
Increases the level of bad cholesterol. Cause
cardiac death
Some occur in meat and dairy products
Majority come from processed foods
Hydrogen atoms are on the opposite side of
the double bonds of the carbon chain,
making the fat molecule straight.
High
Melting point
2. What is radioactive isotope? Describe one application of using radioactive isotope in medicine or
biological research.
a. Radioactive isotopes: is one in which the nucleus decays spontaneously (phân hủy tự phát),
giving off (tạo ra) particles and energy. When the radioactive decay leads to a change in the
number of protons, it transforms the atom to an atom of a different element
-
b. Application of using radioactive isotope in medicine or biological research.
When a radioactive isotope is added in small amounts to comparatively large quantities of the stable
element, it behaves exactly the same as the ordinary isotope chemically
Iodine-131: effective in treating hyperthyroidism (cường giáp)
Carbon-14: used in a breath test to detect the ulcer-causing (gây loét) bacteria Helicobacter pylori.
Cobalt-60 is extensively employed as a radiation source to arrest (prevent) the development of cancer.
3. Describe major differences in photosynthesis among C3, C4 and CAM plants.
C3
C4
CAM
maize, sorghum,
85%: Wheat, soybeans,
Cactuses, tequila agave,
Species
sugarcane, tef, and
potatoes, apple
pineapple.
papyrus
Typical environment
All
Tropical, drought
Dry, semi-arid condition
Stoma: Opening time During day
During day
Night
Steps in pathway
1
2
2
Single carbon dioxide
Double carbon dioxide
Double carbon dioxide
fixation
fixation
fixation
The mesophyll cells (MC)
All leaf mesophyll cells
Vacuoles
Where carbon is fixed
and the bundle sheath
(chloroplast organelles)
cells (BSC).
First molecule
Malic acid or aspartic
3-phophoglyceric acid
Malate
produced in pathway
acid
First stable product
3PGA
OAA (oxalo acetic acid)
OAA (oxalo acetic acid)
First enzyme involved Rubisco
PEP carboxylase
PEP carboxylase
Calvin Cycle
Yes
Yes
Yes
Photorespiration
Present in high
Not easily detectable
Detectable in afternoon
4. Name the three stages of cellular respiration; for each, state the region of the eukaryotic cell
where it occurs and the products that result.
- Stage 1: Glycolysis occurs in the cytoplasm and breaks down glucose into 2 pyruvates + 2 NADH +
2 ATP
- Stage 2:
 Pyruvate oxidation occurs in the mitochondria and produces 2 acetyl CoA and 2 NADH.
 The citric acid Cycle occurs in the matrix mitochondria and produces 2 ATP 6 NADH and 2
FADH2.
- Stage 3: the oxidative phosphorylation which occurs in the inner mitochondria and produces ATP
5. Describe the fluid mosaic model of cellular structure.
The fluid-mosaic model describes the plasma membrane of animal cells: the membrane is a mosaic of
protein molecules bobbing in a fluid bilayer of phospholipids
The plasma membrane has two layers (a bilayer) of phospholipids (fats with phosphorous attached).
Each phospholipid molecule has:
 Hydrophilic: a head that is attracted to water
 Hydrophobic: a tail that repels water
Both layers of the plasma membrane have the hydrophilic heads pointing toward the outside,
contact with the fluid; the hydrophobic tails form the inside of the bilayer  stable boundary
between two aqueous compartments
Proteins and substances such as cholesterol become embedded in the bilayer, giving the
membrane the look of a mosaic. Because the plasma membrane has the consistency of vegetable oil
at body temperature, the proteins and other substances can move across it. That is why the plasma
membrane is described using the fluid-mosaic model.
6. What is epigenetic Inheritance? Explain how histone acetylation affect chromatin structure and
the regulation of transcription?
The inheritance of traits transmitted by mechanisms not directly involving the nucleotide sequence
is called Epigenetic Inheritance
In biology, the term Epigenetics refers to changes in phenotype (appearance) or gene expression
caused by mechanisms other than changes in the underlying DNA sequence, hence the name epi(Greek: over; above) -genetics.
- How histone acetylation affects chromatin structure and regulation of transcription:
Histone acetylation (sự acetyl hóa histone): is the addition of an acetyl group (three carbon molecule)
to a positively charged lysine at one end of a histone molecule. This is catalyzed by the enzyme histone
acetyltransferase (HAT).
 This generally loosens chromatin structure (làm lỏng cấu trúc nhiễm sắc)  active chromatin,
increase transcription ability and promoting the initiation of transcription (quá trình bắt đầu phiên mã)
This process serves as a chemical "switch" that makes some of the nearby genes on the chromatid
more likely to be transcribed into RNA while making others less likely to be transcribed.
7.
Distinguish between the following pairs of terms: dominant and recessive; heterozygous and
homozygous; genotype and phenotype.
Dominants (A, B,..)
Recessive (a, b,..)
The genes responsible for the expression of the
The genes responsible for the expression of the
dominant character
recessive character
Mask the effect of the recessive genes
Unable to mask the effect of the dominant genes
do not require the presence of a similar gene in the
require the presence of a similar gene in the gene
gene pair for the expression
pair for their effect.
more likely to be inherited
less likely to be inherited.
Meaning
It carries
Results in
Type of alleles
Type of gametes produced
Traits
Homozygous (AA, aa)
Diploid organism: identical alleles
Carries similar alleles of a trait
Similar individuals: pure
Dominant or recessive
1
Produce the same traits over
different generations
Heterozygous (Aa)
Diploid organism: different alleles
Carries dissimilar alleles
Dissimilar individual: rarely pure
Both dominant and recessive
2 different
Produce different traits over different
generations
Definition
Depends on
Inheritance
Be determined
by
Genotype (AA, Aa, aa)
The genetic makeup of an individual 
Refers to the information contained on two
alleles in the cell
The hereditary information that was given to
an individual by their parents.
Partly inherited by offspring (one of the
alleles is passed on during reproduction)
Genotyping – using a biological assay (inside
the body)
Phenotype (red, white,..)
Detectable expression of the genotype in
the interaction with the environment. An
expressed and observable trait
Genotype and the influence of the
environment
Cannot be inherited.
Observation of the individual. (Outside the
body)
8. Describe meiosis process and explain how this process contributes to genetic variation in species.
a. Meiosis process: a two-step division process. In each round of division, cells go through four
stages: prophase, metaphase, anaphase, and telophase.
- Meiosis I: Homologue pairs separate during a first round of cell division
 Prophase I: duplicated homologous chromosomes pair and exchange segments
 Metaphase I: chromosomes line up by homologous pairs
 Anaphase I: each pair of homologous chromosomes separates
 Telophase I and cytokinesis: two haploid cells form; each chromosome still consist of two sister
chromatids.
- Meiosis II: Sister chromatids separate during a second round  four haploid daughter cells
result, containing unduplicated chromosomes.
b. Meiosis process contributes to genetic variation in species:
- Crossing Over
During prophase of meiosis I, the double-chromatid homologous pairs of chromosomes cross over with
each other and often exchange chromosome segments. This recombination creates genetic diversity by
allowing genes from each parent to intermix, resulting in chromosomes with a different genetic
complement. The new combination of genes on a chromosome can lead to new traits in offspring.
- Reduction to Haploid
The reduction from the diploid number to haploid and the random distribution of each chromosome
lead to equal distribution of a given chromosome to either of the two daughter cells. By shuffling the
genetic deck in this way, the gametes resulting from meiosis II have new combinations of maternal and
paternal chromosomes, increasing genetic diversity.
- Random Chromatid Assortment
The sister chromatids separate and are randomly distributed to the daughter cells, the gametes. During
anaphase of meiosis II, the centromere joining each chromatid pair dissolves, creating two
chromosomes of each type. The outcome of which chromosome will go to which gamete is random so
that each gamete has a potentially unique combination of genetic material