Download the structures and functions of a Euglena. Draw a Euglena. B

Living Organisms, Microbes, & Genetics NCFE Practice Question Answers
A) Describe the structures and functions of a Euglena. Draw a Euglena.
Eyespot – Helps the Euglena to detect light so it can move to a bright
area to undergo photosynthesis
Nucleus – Control center of the cell
Chloroplast – Where photosynthesis occurs
Flagellum – Tail-like structure that is used for movement
D) Construct an animal cell. Label and describe the major organelles: cell membrane, nucleus,
mitochondria, and vacuoles.
Cell membrane – Protects the cell from the surrounding
environment
Nucleus – Controls and directs the functioning of the cell
Mitochondria – The powerhouse of the cell. Generates energy for
the cell
Vacuoles – Used for storage of food, waste, water, etc.
Cell Membrane – Protective outer layer
B) Describe the structures and functions of a Paramecium. Draw a Paramecium.
Cilia – Small, hair like structures used for movement
Contractile vacuole – stores waste and other substances
and will remove them from the organism.
Gullet – Acts like the mouth and will move food into
vacuoles for storage
Oral groove – acts like the mouth and directs food into the gullet which moves food into a vacuole.
Food vacuole – stores food for the organism until it is needed
C) Compare the structures and functions of an Amoeba and Volvox. Draw a picture of each organism.
Flagella are used for movement
Uses chloroplast to undergo photosynthesis and absorbs food through the membrane
Reproduces both sexually and asexually
Volvox
Moves using pseudopodia and uses it to engulf and
“eat” its food.
Reproduces both sexually and asexually
E) Construct a plant cell. Label and describe the major organelles: cell wall, cell membrane, nucleus,
chloroplasts, chlorophyll, mitochondria, and vacuoles.
Cell Wall – Rigid wall to give the plant structure and
protection
Cell Membrane – semi-permeable membrane that will
allow substances to pass in and out of the cell
Nucleus – Control and directs the functioning of the cell
Chloroplasts & Chlorophyll – Where photosynthesis
occurs. Chlorophyll is located inside the chloroplast and
is what gives the structure its green color
Mitochondria – Generates power for the cell
Vacuole – Storage for water, waste, energy, etc
F) Explain the differences between a plant and animal cell – give at least three.
1. Outside of the cell – Plant cells have a tough outer protective layer call the cell wall. It is rigid and gives the
plant structure and protection. The animal cell has a thin, semi-permeable membrane that surrounds the
cell.
2. Energy – Plant cells have two ways to produce energy for the cell. Its main source is through photosynthesis
using the chloroplast. The plant cell will also use the mitochondria as its back up energy source when
necessary. Animal cells only have the mitochondria as their main power source.
3. Vacuoles – Plant and animal cells both have vacuoles, but the vacuole in the plant cell is much larger than
the ones found in the animal cells.
G) Compare and contrast sexual reproduction and asexual reproduction—give at least three similarities and
differences.


Similarities –
1. Both allow for continuation of the species
Differences –
1. Asexual reproduction only requires one parent and sexual reproduction requires two parents
2. Offspring are 100% identical to their parents in asexual reproduction. The offspring are pretty much
clones of the parents. With sexual reproduction, the offspring only have 50% in common with each
parent.
3. Asexual reproduction occurs most often in unicellular organisms and sexual reproduction happens most
often in multi-cellular organisms.
H) Explain the process of meiosis
I)
Meiosis is a type of cell division that reduces the number of chromosomes in the cell by half to create sex cells
for organisms that undergo sexual reproduction. There are two main stages, Meiosis I and Meiosis II. During
these stages the chromosomes line up randomly and will separate into new cells. This type of independent
assortment with the chromosomes is what gives organisms a lot of genetic variability.
Explain the process of mitosis.
The process of mitosis is used for two main purposes in organisms. First is for growth and development. In
multi-cellular organisms, rapid copying of cells adds to the organism allowing it to grow in size. In multi-cellular
organisms that have reached maximum growth, mitosis renews and replaces older cells to maintain the
organism’s size and function.
J)
Explain why offspring that result from sexual reproduction have greater variation than offspring that result from
asexual reproduction.
In asexual reproduction offspring are 100% identical to their parents. They are basically clones of the parent and
have the same identical traits and features. With sexual reproduction, the offspring only have 50% in common
with each parent. The parents each contribute one chromosome which leads the offspring to look differently
than both of the parents. During meiosis (creation of the sex cells) there is a process call independent
assortment and crossing over. This allows the parents’ chromosomes to become even more assorted and will
lead to an even greater variation between the offspring.
K) Name AND describe two ways of identifying traits in people.
1. Punnett Square – This chart is used to help determine the probability that an offspring will have a certain set
of genetic traits based on the traits of their parents.
2. Pedigree Chart – This chart is similar to a family tree and is used to trace the passing of a certain trait
through a family. This will be used to predict the probability that a couple will pass a certain trait on to their
offspring. This is most often used to trace genetic disorders.
L) Describe the relationship between traits AND heredity
Heredity is the passing of traits from parent to offspring. Traits are the genetic characteristics that are passed
from parent to offspring.
M) Explain the difference between dominant AND recessive traits
A dominant trait is the form of the gene that will always show up in an organism if present and working
correctly. It is typically represented by the first capital letter of the dominant allele for a trait - Ex.) Seed shape:
round (R). The recessive trait is the form of the gene that will only show up if the dominant allele is not present
or working correctly. It is typically represented by the lower case letter of the dominant allele for a trait - Ex.)
Seed shape: wrinkled (r).
N) Explain how genes and alleles are related to genotype and phenotype.
Genotype – This is the genetic make-up of an organism. It tells you which type of alleles that the
offspring has for each specific gene. Example - Gg
Phenotype – This is the physical appearance of an organism. It tells you how the genes and alleles are
being expressed. Example – Green pod color
O) Explain the difference between heterozygous AND homozygous.
Heterozygous – This term is used to describe the allele combination that an organism has. Heterozygous means
that the organism has two different alleles for the gene. They will have one dominant and one recessive allele
for that specific trait. We also use the term hybrid for heterozygous.
Homozygous - This term is used to describe the allele combination that an organism has. Homozygous means
that the organism has two of the same alleles for the gene. They will have two dominants alleles or two
recessive allele for that specific trait. We also use the term purebred for homozygous.
P) Name AND describe two genetic disorders.
1. Albinism – This is a recessive disorder where I person has little or no pigmentation in the skin
2. Colorblindness – This is a sex-linked disorder that happens most often in men, but can rarely occur in
women. The most common form of colorblindness does not allow the person to distinguish between the
colors red and green.
3. Down syndrome – This occurs when a person receives three copies of the 21st chromosome instead of the
normal two copies. The extra copy causes problems with the way the body and brain develop. It is the most
common birth defect in humans.
4. Hemophilia – A sex-link disorder that is most common in men and happens rarely in women. This is a
clotting disorder where a person’s blood clots very slowly or not at all.
5. Marfan’s Syndrome – A dominant disorder dealing with the connective tissue. This can lead to a person
going abnormally tall and having an arm span that is longer than their height.
6. Sickle-Cell Disorder – A co-dominant disorder that causes the red blood cells to form in a sickle shape. This
can lead to clotting of blood in the body and increase a person’s risk for stroke and heart attack. A person
with sickle cell or with one sickle cell allele is also immune to malaria.
Q) Create and solve a Punnett Square using the alleles: male- GG female- Gg
G
G
g
GG
Gg
G
GG
Gg
R) Explain how the environment and lifestyle choices can impact an organism’s survival---give at least
three examples.
1. If someone with hemophilia plays contact sports then he is putting himself at risk because if he gets cut or
bruised he could heavily bleed and may not be able to get it under control. Hemophilia’s have trouble with
their blood clotting so putting themselves at risk to get cut or bruised would not be wise.
2. If someone with albinism stays out in the sun then he is putting himself at risk to get sunburn or worse, skin
cancer. This is because the person lacks melanin, which helps protect a person from the sun. Albino’s should
always use sunscreen and wear protective clothing.
3. If a person with sickle cell disease eats a diet high in fats and cholesterol, they are putting themselves at an
even higher risk for a heart attack than they already are due to the shape of their red blood cells.
Pedigree Chart: Colored in shape= Black Fur / Non-Colored in shape= White Fur
Black Fur
White Fur
Aa
I
II
III
Aa
Aa
aa
Aa
A?
A?
aa
A?
aa
aa
aa
aa
aa
Aa
Aa
T) Explain why three of I-1 and I-2 offspring had mice with black fur and one with white fur.
Black fur is the dominant trait. Three of their offspring received at least one capital B which means that the dominant
trait will be the one that is shown. The fourth offspring received two recessive alleles or two lower case letters which
allowed the recessive allele to be shown.
U) Compare and contrast the two families in the above pedigree chart.
The family on the left had more dominant traits in the first two generations than the second family.