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BZ 104
exam 1
67
Biology
Undergraduate 2
02/05/2011

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Term
Three major groups of living organisms
Definition
• Archaea
• Bacteria
• Eukarya
Term
• Eukarya
o
Definition
Animals
o Plants
o Algae
o Fungi
Term
PHOTOSYNTHESIS
Definition
• Production of organic molecules from inorganic molecules with the use of light energy
• 6CO2+ 6H2O = C6H12O6+ 6O2
• Carbon dioxide + water = Glucose + Oxygen
Term
Characteristics of Plants:
Definition
• Photosynthetic
• Immobile
• Terrestrial
• Multi-cellula
Term
Plants that are not green
Definition
1. Parasitic Plants
Obtain food from by other HOST plants
Examples: Mistletoes, sandalwood, dodde

Saprophytic plants – depend on decaying
organic matter for nutrition
Indian Pipe, Monotrop

Carnivorous plants – feed on insects
Pitcher plant, Nepenthes
Term
Role of plans
Definition
Plants produce half of all the oxygen
present in the atmosphere
Oxygen is a by product of photosynthesis

Plants help lower the level of carbon
dioxide gas in the atmosphere
Rarely recognized ecological service
Plants convert CO2
to organic compounds.

Plants are the primary producers and
provide the food supply for all other
organisms on the earth

4. Plants interact with other organisms and
form close associations
Symbiosis –

Plants use some of the photosynthetic
products to construct lignin.
Lignin is a major constituent of wood.
Term
What is Science?
Definition
Body of knowledge and a process
• Exciting
• Useful
• Ongoing
• Global human endeavor
Term
To be a scientific statement:
Definition
1. A statement must be TESTABLE
2. The tests must be REPEATABLE and
REPRODUCIBLE
Term
Scientific process
Definition
of observation, measurement
and experimentation reduces the probability of
a scientific statement being wrong.
Term
The Scientific Method
Definition
Observation: Prevalence of pale colored
moths in unpolluted areas and dark moths
in polluted areas
1. Question: What is causing this pattern of
moth distribution?
2. Hypothesis: Birds are able to capture
moths that contrast their background
– Null Hypothesis: Both pale and dark colored
moths survive equally well in polluted areas.3. Empirical test: Pale and dark colored
moths were released in two aviaries – one
with polluted (dark) background and the
other with unpolluted (light) background.
Birds were allowed to hunt for the moths.
4. Data: Determine the frequency of pale
and dark moths after a few days.
Moths that didn’t match their backgrounds
were preferentially taken by the birds.5. Conclusion: Reject the null hypothesis.
Both pale and dark colored moths survive equally
well in polluted areas – Rejected.
Prevalence of pale colored moths in unpolluted
areas is because they can survive better from
bird predators if they can blend with the
background
6. Prediction: When polluted areas are
cleaned, pale colored moths will be
expected to increase in frequency.
Term
Greenhouse gases
Definition
CO2
, Methane, water vapo
Term
Who discovered cells and cell theory?
Definition
Cells were discovered in 1665 by Robert Hooke.
Cell Theory was developed around 1838 by
Schleiden and Schwann
Term
What are the advantages of cells being
small?
Definition
Cell size ranges from about 1 micrometer to 100
micrometers

Small size maximizes cell surface area to its volume.

CELL SURFACE AREA – Surface through which material is exchanged
Term
All cells contain the following 3 components
Definition
1. Cell membrane – defines the outer limits
• Made up of phospholipids
2. Cytoplasm – watery solution that
includes other cell structures
3. Ribosome – protein synthesis
machinery of the cell
• Made up of protein and RNA
Term
Difference between
1. Primary and secondary cell wall
Definition
Main structural component of cell walls is
cellulose.
– Primary cell wall – found in growing cells
maintaining the ability to stretch
– Secondary walls are derived from primary
walls as cells mature by thickening and
including lignin.
CELL WALLS ARE PRESENT ONLY IN PLANT
CELLS
Term
Difference between

2. Prokaryotes and eukaryotes
Definition
Term
DNA
Definition
contains genetic information organized
into GENES
Term
RNA
Definition
copies and translates the information in DNA into protines
Term
Important properties of water that make it
essential for life:
Definition
1. Exists as solid, liquid and gas at earth’s
temperatures
2. Dissolves many substances
3. Cohesive property
4. Ice being less dense that water floats on
water
Term
Cohesion
Definition
Hydrogen bonds make
water molecule COHESIVE
cohesive – to stick together
This helps plants draw water up
from the soil through their
roots and expel water vapor
from leaves.
Term
Carbohydrates
Definition
Include sugars, starches and cellulose
Simple sugars or MONOSACCHARIDES – glucose,
fructose which are the basic energy molecules
DISACCHARIDES – sucrose is the main sugar
transported in plants – short term storage
POLYSACCHARIDE – starch is used for energy
storage and cellulose is a structural component
Term
Fatty acids,
Definition
Fats and oils can be differentiated based on their
FATTY ACIDS
Fats – saturated fatty acids
Oils – unsaturated fatty acids
Saturated fatty acids – all carbon atoms are linked to
the maximum hydrogen atoms possible.
Term
Proteins
Definition
Most abundant organic molecule
They are composed of amino acids linked by peptide
bonds
Most important function is that of being biochemical
catalysts called ENZYMES.
Enzymes regulate metabolism
Term
Nucleic Acids
Definition
They contain genetic information for all
structures and functions
Nucleic acids contain nucleotides that are made up of
5-carbon sugar (ribose)
a phosphate group
a nitrogen-containing base
Term
Terpenes or terpenoids
Definition
Serve the role of attracting or repelling insects.
Some plants like rose and lavender have pleasant
fragrances due to terpenes that attract insect
pollinators
Term
Phenolics have antiseptic properties
Definition
Flavonoids in red grapes, blueberries and other
fruits
Tannins in unripe fruits and leaves are
toxic to herbivores.
Flavor compounds in spices such as
cinnamon, vanilla, nutmeg …
are also phenolics
Term
Alkaloids are used as medicines
Definition
Quinine from Cinchona – controls malaria
While the malaria causing organism is resistant to
synthetic quinine it is NOT resistant to quinine
from the natural source
Term
PLASTIDS
Definition
Chloroplasts – green plastids – contain
chlorophyll
• Amyloplasts – non-green – store starch
• Chromoplasts – colored pigments that
color leaves, flowers and fruits with red,
orange or yellow colors
Term
Mitochondria
Definition
– site of energy production
– POWER HOUSE OF THE CELL
• Site of cellular respiration
Term
Role of Vacuoles in plant cells
Definition
Plant vacuoles maintain water pressure in
cells

Allows accumulation of substances
3. Storage compartment for acids in citrus
fruits, red, blue and purple pigments in
flowers and fruits, sugar in sugar beet and
sugarcane
4. Also store defensive compounds such as
tannins, heavy metals …
Term
Phytoremediation
Definition
Metal-rich plants are harvested for metal extraction
or are buried in toxic storage areas
Term
Cell cycle – interphase and mitosis – when does cell division occur
Definition
The life of a cell – CELL CYCLE
Cell cycle = duplication + cell division

In eukaryotes the cell cycle is divided into
1. Interphase – stage when the cell
prepares for division
2. Mitosis phase – process of cell division
Eukaryotic cells spend most of their cell cycle in INTERPHASE
Term
Mitosis
Definition
Mitosis is the process of cell division that
produces two daughter cells with equal
amounts of DNA and other substances.
– Each daughter cell is an exact copy of the
parent cell.
– In plants Mitosis occurs in meristems –
growing parts of the plants.
Term
Phases during mitosis
Definition
Prophase
2. Metaphase
3. Anaphase
4. Telophase
5. Cytokinesis – cytoplasmic division
Term
What happens during the S, G1 and G2
phases?
Definition
Interphase also the period when cells are not
dividing.
3 phases
1. G1
– Gap 1 – Cell increases in size and
ribosomes are produced.
2. S – Synthesis – DNA replication takes
place.
– Amount of DNA in the cell has doubled
3. G2
- Gap 2 – Mitochondria divide, and
protein synthesis increases.
Term
• Differences between DNA & RNA and Base pairing
Definition
DNA molecules consist of a 5-carbon
sugar (DEOXYRIBOSE), a phosphate
group and 4 different nitrogen bases
• Bases: Adenine (A), Guanine (G),
Cytosine (C) and Thymine (T)

Ribose sugar,
• N-bases – A,U,C,G
• Pairing: A with U and C with G
3 kinds of RNA:
1. mRNA – messenger RNA
2. tRNA – transfer RNA
3. rRNA – ribosomal RNA
Term
Synthesis of a complementary strand, DNA replication, functions of DNA polymerase
Definition
DNA Polymerase – enzyme involved in the
synthesis of complementary strands
Functions of DNA polymerase:
1. Recognize each N-base in the original
strand
2. Bring the nucleotide with the
complementary N-base
3. Bind the nucleotide to the growing strand
Term
• What is the importance of semi-conservative replication?
Definition
helps
reduce errors during replication.
Term
What is a mutation? Why are mutations so rare?
Definition
DNA is double stranded – 2 copies of genetic
information. Damage to both strands is rare.
One strand is used as template for correction
2. DNA REPAIR NUCLEASES recognize and
remove damaged DNA strands
3. Damaged length is cut out. DNA POLYMERASE
fills the gap with new nucleotides
4. DNA LIGASE seals the break and completes the process of repair

If mistakes are not corrected or repaired –changed DNA is transmitted to the next generation of cells

A change in genetic information is called MUTATION.


Most mutations are harmful and letha
Term
• RNA – transcription and translation locations in a cell, types of RNA molecules
Definition
Transcription – Genetic information in DNA to messenger RNA (mRNA) Occurs in the nucleus

Translation – coded instructions in mRNA into a sequence of amino acids by transfer RNA (tRNA).Occurs in the cytoplasm
Term
Synthesis of mRNA strand from a DNA strand
Definition
Transcription – Genetic information in
DNA is transcribed into mRNA.
Occurs in the nucleus
Information is copied from DNA into
mRNA
Term
Genetic code or triplet code or codon, features of the genetic code, commercial use of the properties of genetic code
Definition
It is called the TRIPLET CODE and each
triplet is a CODON

Genetic code – set of 3 nucleotides that
code for an amino acid – triplet code
Features of the triplet code…1. Most triplets code for one amino acid
UGG – Tryptophan …
2. Some amino acids have more than one triplet
coding for them
AAA, AAG – Lysine, …
3. Some codes signal the start of translation
AUG codes for Methionine – START CODON
AUG signals the start of protein synthesis4. A few triplets do not code for any amino acid at
all.
Such triplets, instead signal the stop of protein
synthesis and are called STOP CODONS.
Term
What is mitosis? How does it progress through its different stages?
Definition
Mitosis is the process of cell division that
produces two daughter cells with equal
amounts of DNA and other substances

1. Prophase
2. Metaphase
3. Anaphase
4. Telophase
5. Cytokinesis – cytoplasmic division
Term
1. What are chromosomes? Parts of a chromosome
Definition
In Prophase• Chromosomes condense.
– Strands of chromatin coil forming chromatids
– Centromeres holding each pair of chromatids together.
Term
What happens in each stage of mitosis
Definition
1. Prophase
– condensation of
chromosomes
2. Metaphase
– Chromosomes align at the
cell’s equator
3. Anaphase
– Sister chromatids separate
and move towards the poles
4. Telophase
– Chromosomes reach the
poles and become chromati
Term
What is the importance of sexual reproduction and which type of cell division is critical and unique to it
Definition
Sexual reproduction requires genetic contribution from two
sex cells (gametes), which unite to form a zygote.
Term
What is meiosis? How does it differ from mitosis
Definition
Unlike mitosis, the centromere does not divide. One entire
chromosome (consisting of 2 chromatids) from each
homologous pair, is pulled into each daughter cell.
At the end of Meiosis I, each of the two daughter cells
contains one chromosome of each homologous pair
(therefore haploid) but as each chromosome still contains the
two chromatids, each cell has twice the amount of DNA
Term
What are homologous chromosomes
Definition
break and exchange genes,
increasing the amount of genetic variation. Recombination
frequency of two loci is directly proportional to the distance
between them.
Term
What is genetics?
Definition
Science of heredity – how do offspring inherit
characters from their parents
– Selective breeding for characters
• Study of genes – what are genes? How do they
work? How do genes control the expression of
characters?
– Nature Vs Nurture  Genes Vs Environment
• Two individuals, even siblings, are never exactly
the same. Why?
• What causes variation amongst the individuals of
a species
Term
The “blending” hypothesi
Definition
characters of the
two parents blend in the offspring
Term
The “blending” hypothesis
Definition
characters of the
two parents blend in the offspring

NOT CORRECT-but the
Term
The “particulate” hypothesis – )
Definition
parents pass
on discrete heritable units (genes
Term
Mendelian Laws of Inheritance
Definition
1. Law of segregation

Characters do not blend in the offspring
During meiosis in the offspring with Gg
Anaphase I – homologous chromosomes move
apart
Alleles on homologous chromosomes segregate
independent of each other
2. Law of independent assortment
Characters
on different homologous chromosmes assort
independently during meiosis
Mendel’s second law – describes the inheritance
of two characters
• Genes located on different pairs of
homologous chromosomes assort
independently during meiosis.
Term
Blending inheritance VS Particulate Inheritance
Definition
The “blending” hypothesis – characters of the
two parents blend in the offspring

The “particulate” hypothesis – parents pass
on discrete heritable units (genes)
• Characters DO NOT BLEND IN OFFSPRING
Term
Mendelian Laws of Inheritance
Definition
1. Law of segregation
2. Law of independent assortmen
Term
Incomplete dominance
Definition
The phenotype of the hybrid is an intermediate of
the phenotypes of the two parents
NO DOMINANCE
But alleles still segregate independently during
meiosis – Law of segregation holds
NO DOMINANCE IS NOT BLENDING.
Term
Dominant
Definition
An allele that is expressed regardless of the
corresponding allele.
Term
Recessive
Definition
An allele that must be homozygous for it
to be expressed.
Term
Genotype
Definition
Genetic makeup or an allelic combination (Tt)
Term
Phenotype
Definition
The visible characteristic corresponding to a
genotype (Tall Tt or TT).
Term
Deviations from Mendel’s Laws
Definition
1.When alleles are not completely dominant or
recessive – Incomplete dominance
2.When one gene has more than two alleles –
Polygenic inheritance
3.When one gene produces multiple phenotypes –
Pleiotropy
4. Gene interaction
1. Linkage – More than one gene on the same
chromosome
2. Environment – character changes with environment
Term
POLYGENIC INHERITANCE
Definition
Each allele in the group makes a small contribution to
the phenotype – dosage effect.
Traits show a wide range of variation – continuous
variation
Traits that show continuous variation follow –
Polygenic inheritance
Term
Pleiotropy
Definition
One gene can affect multiple traits and
alter the phenotype

A gene that influences more than one
phenotype – pleiotropic gene
Pleiotropic effect is seen only in the
PHENOTYPE
Term
Linked Genes
Definition
There are many more genes the total
number of chromosomes in any organism
Each chromosome MUST bear many
genes
Genes present on the same chromosome
are said to be LINKED
Linked genes are likely to be inherited
together
Term
Sex chromosomes
Definition
Flowers of most plants have both anthers
(male) and ovaries (female) parts –
Sexually monomorphic
(Hermaphrodites)
Sexually dimorphic plants
Have sex (X & Y) chromosomes that
determine gender
XX – female plant (only ovaries)
XY – male plant (only anthers).

6% of flowering plants – sexually dimorphic
Term
Advantages of GM organisms
Definition

Allows genes from a much wider range of 

organisms to be inserted into plants or bacteria

– Not restricted to distant relatives of crop plants

• GE changes can be made much more quickly –

Modern molecular techniques – insert genes into 

chromosomes within a few weeks Advantages of GE:

• Induce mutations to create new traits

– New and previously non-existent in both wild and 

cultivated populations

GE makes it possible to tailor crop plants to suit 

needs and demands of humans

 Short and pest resistant cotton plants – ease of harvest

 Tomatoes with delayed ripening – longer storage

 Virus resistant papaya

 Rice with beta-carotene 

Term
Concerns about indiscriminate spread of gm technology
Definition

Biotechnology claims to solve world food 

problems

Patenting of GM crops by large companies

• GM seeds cost much more than regular seeds 

– Farmers in poor countries or poorer farmers in the US 

cannot afford GM seeds

• Farmers usually collect seeds at the end of a 

season – for next planting 

– Patenting of GM seeds makes it illegal to collect 

seeds• World’s most serious concern – unchecked 

growth of human population

– Water and fossil fuels – serious concerns and 

will continue to be problems

Ever increasing world population is the 

problem that needs immediate attention

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