KaiserScience

Home » Plants

Category Archives: Plants

MCAS Plants

MCAS Plant questions from the Biology MCAS

February 2018

Screen Shot 2019-10-23 at 9.34.04 AM

____________________

31. A plant species growing along a coast produces seeds with fluffy hair-like
fibers on one end. A seed from one of the plants is shown below:

Seed fluffy fiber

Some of these seeds were dispersed by the wind to islands off the coast, where new plants grew. Within 10 years, the seeds of the island plants were different
from the seeds of the mainland plants. Compared to the mainland seeds, the
island seeds were heavier and had shorter hair-like fibers. Which of the following statements best explains why heavier seeds with shorter fibers were favored in the island environment?

A. These seeds carried more genes than the mainland seeds did.
B. These seeds were less likely to be blown off the island by wind.
C. The island plants needed to prevent animals from eating the seeds.
D. The island plants used more energy to produce heavy seeds than to grow.

____________________

33. Students investigated the effect of acid rain on photosynthesis. Several plants
were given water with a pH of 4 each day for two months. The results showed
that the plants had a reduced rate of photosynthesis.

How did the acidic water most likely reduce the plants’ rate of photosynthesis?

A. by storing excess oxygen produced by the plants
B. by changing the effectiveness of enzymes in the plants
C. by causing root hairs to grow on the roots of the plants
D. by increasing the amount of carbon dioxide taken in by the plants

____________________

34. Waxes form a waterproof coating over the stems and leaves of many terrestrial plants. The waxes are composed of fatty acids linked to long-chain alcohols. Based on this information, waxes are which type of organic molecule?

A. lipids .  B. nucleotides .  C. polysaccharides .  D. proteins

____________________

37. Maltose is a carbohydrate molecule that provides energy to plants early in their
life cycle. Which elements are most common in a molecule of maltose?

A. carbon and hydrogen
B. copper and nitrogen
C. iron and phosphorus
D. magnesium and sulfur

____________________

Algae, and the scientific method

The rate of photosynthesis in organisms depends in part on the wavelength of visible light. In the late 1800s, Thomas Engelmann demonstrated the relationship between the wavelength of light and the rate of photosynthesis. His experiment is described below.

• Engelmann used a prism to produce a visible light spectrum of violet, blue, green, yellow, orange, and red light.
• He shined the light spectrum onto cells of the algae Spirogyra.
• Once the light was shining on the Spirogyra cells, Engelmann added aerobic bacteria to the system. Aerobic bacteria need oxygen to live and grow.
• After adding the bacteria, Engelmann observed the regions of the light spectrum where the bacteria concentrated around the Spirogyra cells.

The setup and results of Engelmann’s experiment are represented by the diagram below:

Engelmann’s experiment Spirogyra algae spectrum prism

Mark your answers to multiple-choice questions 8 through 11 in the spaces provided in your Student Answer Booklet. Do not write your answers in this test booklet, but you may work out solutions to multiple-choice questions in the test booklet.

8. Why are the greatest numbers of aerobic bacteria found at the 400–500 nm and 600–700 nm wavelengths of light?

A. Photosynthesis rates are highest there, producing large amounts of water.
B. Photosynthesis rates are highest there, producing large amounts of oxygen.
C. Photosynthesis rates are lowest there, producing small amounts of glucose.
D. Photosynthesis rates are lowest there, producing small amounts of carbon dioxide.

9. What is the role of visible light when Spirogyra cells perform photosynthesis?
A. It provides the energy for the photosynthesis reaction.
B. It concentrates the photosynthesis products for export.
C. It activates the DNA that directs the photosynthesis reaction.
D. It transports photosynthesis reactants across the cell membrane.

10. What is exchanged between the Spirogyra and the bacteria in
Engelmann’s experiment?

A. DNA and RNA
B. starch granules and spores
C. chlorophyll and cytoplasm
D. oxygen and carbon dioxide

11. A scientist used Engelmann’s data to predict how the concentrations of different substances in and around Spirogyra cells will change when the cells are exposed to different wavelengths of light. A graph for one substance is shown below.

Screen Shot 2019-10-23 at 9.50.51 AM

What is represented on the y-axis?

A. chlorophyll concentration .        B. hydrogen concentration
C. oxygen concentration .        D. water concentration

____________________

Spring 2018 MCAS

3. All corn plants contain the ZmLA1 gene. Some corn plants contain a certain mutation in the ZmLA1 gene. The graph below shows the amount of ZmLA1 RNA produced in plants with the normal gene and in plants with the mutated gene.

Screen Shot 2019-10-23 at 9.54.47 AM

Based on the graph, what most likely happens in corn plant cells as a direct result of the mutated gene?

A. DNA replication increases.
B. Lipid production decreases.
C. Glucose synthesis increases.
D. Protein production decreases.

____________________

4. The growth of plants in many ecosystems is limited by the supply of
nitrogen. Which of the following groups of organisms plays the largest role in
moving nitrogen between the atmosphere and plants?

A. bacteria .      B. earthworms .      C. insects .    D. protists

____________________

7. Lithops are multicellular organisms found in sandy soil in deserts. They
have large, central vacuoles in their cells that store water. Which of the following best classifies lithops?
A. They are bacteria because they store water.
B. They are animals because they are multicellular.
C. They are fungi because they are found in sandy soil.
D. They are plants because they have large, central vacuoles.

____________________

14. There are many fungus species that live inside plant tissues. What determines
whether the relationship between a fungus and a plant is commensalism,
mutualism, or parasitism?

A. where the fungus is located in the plant
B. how long the fungus survives in the plant
C. whether the fungus reproduces in the plant with spores, seeds, or runners
D. whether the effect of the fungus on the plant is neutral, positive, or negative

____________________

37. Plants in floodplains often get covered by water during floods. Some
plants survive the floods because they can continue photosynthesis
underwater. However, the plants’ rates of photosynthesis are much lower
underwater than above water.

Which of the following helps to explain why the rates of photosynthesis are
lower underwater than above water?

A. There is too much oxygen in the water.
B. There is no carbon dioxide in the water.
C. The chloroplasts do not function underwater.
D. The available light is less intense underwater.

____________________

February 2017

17. Carbon fixation is an important part of the carbon cycle. Carbon fixation is the conversion of carbon dioxide into organic compounds such as glucose. Which of the following organisms cannot fix carbon?

A. grass
B. green algae
C. mushrooms
D. oak trees

____________________

3. A botanist studied two groups of rice plants to determine how they are related. Both groups of plants have similar shapes, but one group has longer stalks. When the botanist cross-pollinated plants from one group with plants from the other group, the seeds produced did not sprout or grow.

Which of the following conclusions is best supported by this information?

A. The two groups are the same species because the plants have similar shapes.
B. The two groups are different species because they have differently sized stalks.
C. The two groups are different species because the seeds produced cannot sprout or grow.
D. The two groups are the same species because the plants were cross-pollinated and produced seeds

____________________

20. A partial food web is shown below. Which organisms in the food web are both primary and secondary consumers?

Screen Shot 2019-10-23 at 10.08.21 AM

A. bluegills
B. cattails
C. coyotes
D. snakes

____________________

28. A student looks at a cell under a microscope. Which of the following
observations would indicate that the cell is from a plant rather than an animal?

A. a nucleus located inside of the cell
B. numerous cilia on the outside of the cell
C. chloroplasts in the cytoplasm of the cell
D. a thin membrane around the edge of the cell

____________________

30. Prolonged periods of drought in an area cause decreases in plant population
sizes. Which of the following statements describes how the decreases in plant
population sizes then affect other populations in the area?

A. Omnivore population sizes increase, and herbivore population sizes increase.
B. Omnivore population sizes decrease, and carnivore population sizes increase.
C. Herbivore population sizes increase, and carnivore population sizes decrease.
D. Herbivore population sizes decrease, and carnivore population sizes decrease.

Green algae

Are green algae plants?

Red algae and brown algae aren’t plants – they’re protists – an entirely different kingdom of life.

Blue-green algae – photosynthetic bacteria.

But what about green algae – are they plants?

It depends on whom you ask:

Green Algae_Pond

Image from Slideshare.net/VijayaraghavanGonuguntla/effluent-treat

Types of algae

The Green Algae Tree of Life (GrAToL)

Botanists (plant scientists) consider green algae plants:

They perform photosynthesis using chlorophyll.
They are the ancestors of modern day land-plants.
They’re part of the land-plant family tree.
End of story -> Plants! 🙂

Zoologists (animal and protist scientists) classify green algae as protozoans (not plants)

In this view, green algae can’t be plants because:

1) Most are single-celled (unicellular), too small to be seen without a microscope.
2) When not single celled, they live in colonies. Don’t form plant tissue.
3) They can move on their own. Some swim with flagella.
4)  They have no vascular system to transport nutrients.
5) They do not have true roots, shoots, or veins.
6)  They have no stems, leaves or roots.

Why can’t the answer be a simple “yes they are” or “no they are not?” Because life wasn’t created with well-defined boundaries – and life today still doesn’t have such boundaries. Life started as simple organisms, and developed over time, slowly branching out to create new forms, with new characteristics. Today’s green algae resembles the early forms of life that later gave rise to both plants and to protists.  It is a kind of “living fossil.

Plant and green algae family tree

Plant Green Algae Prasinophytes chlorophytes clade

from Leliaert F., Verbruggen H. & Zechman F.W. (2011) Into the deep: New discoveries at the base of the green plant phylogeny. BioEssays 33: 683-692

Frederik Leliaert writes:

This figure shows the phylogenetic relationships among the main lineages of green plants. The tree topology is a composite on accepted relationships based on molecular phylogenetic evidence. Uncertain phylogenetic relationships are indicated by polytomies. The divergence times are rough approximations based on the fossil record and molecular clock estimates. These age estimates should be interpreted with care as different molecular clock studies have shown variation in divergence times between major green plant lineages.  Drawings illustrate representatives of each lineage.

Source: Leliaert F., Verbruggen H. & Zechman F.W. (2011) Into the deep: New discoveries at the base of the green plant phylogeny. BioEssays 33: 683-692

 

Learning Standards

Massachusetts Science and Technology/Engineering Curriculum Framework

Life Science (Biology), Grades 6–8. Classify organisms into the currently recognized kingdoms according to characteristics that they share. Be familiar with organisms from each kingdom.

Biology, High School – 5.2 Describe species as reproductively distinct groups of organisms. Recognize that species are further classified into a hierarchical taxonomic system (kingdom, phylum, class, order, family, genus, species) based on morphological, behavioral, and molecular similarities.

Benchmarks for Science Literacy, American Association for the Advancement of Science

Students should begin to extend their attention from external anatomy to internal structures and functions. Patterns of development may be brought in to further illustrate similarities and differences among organisms. Also, they should move from their invented classification systems to those used in modern biology… A classification system is a framework created by scientists for describing the vast diversity of organisms, indicating the degree of relatedness between organisms, and framing research questions.

SAT Biology Subject Area Test

Evolution and diversity: Origin of life, evidence of evolution, patterns of evolution, natural selection, speciation, classification and diversity of organisms.

Teaching About Evolution and the Nature of Science, National Academy Press (1998)

Biological classifications are based on how organisms are related. Organisms are classified into a hierarchy of groups and subgroups based on similarities which reflect their evolutionary relationships. Species is the most fundamental unit of classification.

 

Angiosperms and Gymnosperms

Intro

Angiosperms

There are over 250,000 species of angiosperms. Angiosperms are flowering plants. They make up around 80 percent of all the living plant species on Earth.

  • Dicots

  • monocots

Angiosperm resources

PBS Natureworks: Angiosperms

Gymnosperms

{excerpted from http://education-portal.com/academy/lesson/gymnosperms-characteristics-definition-types.html }

Gymnosperms were the first plants to have seeds.
They have naked seeds – as they do not have flowers
The seeds develop on the surface of the reproductive structures of the plants, rather than being contained in a specialized ovary.
These seeds are often found on the surface of cones and short stalks.

Characteristics of Gymnosperms
They do not have an outer covering (shell) around their seeds.
They do not produce flowers.
They do not produce fruits.
They are pollinated by the wind.

Examples include conifers

conifers

Gymnosperm resources

Education Portal: Gymnosperms

Study.com gymnosperms-characteristics-definition-types

Monocot versus dicot

Two types of seeds, monocots and dictos.

monocot v dicot seeds

Let’s watch the two types sprout:

Grass (monocot) sprouting on left. The cotyledon remains underground and is not visible). Compare to a dicot sprouting on the right.

Monocot_vs_dicot_sprouting

{ http://en.wikipedia.org/wiki/Monocotyledon }

What kinds of plants come from these different types of seeds?

Monocot plants versus dicot plants

monocot v dicot

Comparison chart

Gymnosperms vs angiosperms

 

Learning Standards

Massachusetts Science and Technology/Engineering Curriculum Framework

Life Science (Biology), Grades 6–8.
Classify organisms into the currently recognized kingdoms according to characteristics that they share. Be familiar with organisms from each kingdom.

Biology, High School
5.2 Describe species as reproductively distinct groups of organisms. Recognize that species are further classified into a hierarchical taxonomic system (kingdom, phylum, class, order, family, genus, species) based on morphological, behavioral, and molecular similarities.

Benchmarks for Science Literacy, American Association for the Advancement of Science

Students should begin to extend their attention from external anatomy to internal structures and functions. Patterns of development may be brought in to further illustrate similarities and differences among organisms. Also, they should move from their invented classification systems to those used in modern biology… A classification system is a framework created by scientists for describing the vast diversity of organisms, indicating the degree of relatedness between organisms, and framing research questions.

SAT Biology Subject Area Test

Evolution and diversity: Origin of life, evidence of evolution, patterns of evolution, natural selection, speciation, classification and diversity of organisms.

Teaching About Evolution and the Nature of Science, National Academy Press (1998)

Biological classifications are based on how organisms are related. Organisms are classified into a hierarchy of groups and subgroups based on similarities which reflect their evolutionary relationships. Species is the most fundamental unit of classification.