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Biology - Protista

This document provides study materials related to Biology - Protista. It may include explanations, summarized notes, examples, or practice questions designed to help students understand key concepts and review important topics covered in their coursework.

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Study GuideBiology–Protista1. AlgaeAlgaeare a large and diverse group of organisms that can make their own food using photosynthesis.They may beunicellular (single-celled)ormulticellular, and all of them areeukaryotes, meaningtheir cells have a nucleus.Even though algae look plant-like, they arenot classified as plants. They are considered plant-likebecause they containchloroplasts with chlorophyll, which allow them to carry out photosynthesis.Most algae live in theoceans, but many species are also found infreshwater environmentssuch aslakes and ponds.Scientists divide algae into several majordivisions(instead of phyla, which are used for protozoa).These divisions are mainly based on thetypes of pigmentsthe algae contain and theiroverallcolor. The main divisions are:•Rhodophyta•Pyrrophyta•Chrysophyta•Phaeophyta•Chlorophyta1.1Rhodophyta (Red Algae)Rhodophytaincludes thered algae, which are found almost entirely inmarine (saltwater)environments.•Most red algae areunicellular, but some aremulticellular.•Larger forms grow attached to rocks below thelow-tide level, and some are large enough tobe calledseaweeds.•They carry out photosynthesis usingchlorophyll a.

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Study Guide•Their red color comes from pigments that are similar to those found incyanobacteria.A very important product made from red algae isagar. Agar is widely used in laboratories as asolidgrowth medium for bacteria.1.2Pyrrophyta (Dinoflagellates)The divisionPyrrophytaincludes organisms calleddinoflagellates.•Dinoflagellates areunicellularand often have thick protective plates, giving them anarmored appearance.•They move usingtwo flagella, which help them swim.•Many dinoflagellates arebioluminescent, meaning they give off light when disturbed, suchas by waves or movement in the water.Under ideal ocean conditions, dinoflagellates can reproduce very rapidly. When this happens, theirred pigments can cause the water to turn areddish color, a phenomenon known asred tide.1.3Chrysophyta (Golden Algae)Members of the divisionChrysophytaare known asgolden algae, and most of them arediatoms.•Diatoms have unique cell walls made ofsilica(a glass-like material).•Their cell wall is formed oftwo overlapping halves, similar to a box with a lid.•Diatoms are photosynthetic and play a crucial role inmarine food chains, serving as a majorfood source for many organisms.Over time, the silica shells of diatoms can accumulate and form a porous rock calleddiatomaceousearth. This material is processed intodiatomite, which is used:•as afiller,•as anabsorbent, and•as afiltering agent.

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Study Guide1.4Phaeophyta (BrownAlgae)The divisionPhaeophytaincludes thebrown algae, which are allmulticellular.•These algae are found almost exclusively insaltwater.•Common examples includerock weedsandkelp, some of which can grow to very largesizes.Even though brown algae can be huge, their internal structure ismuch simpler than that of trueplants. Many brown algae are harvested and used as:•fertilizers, and•sources ofiodine.1.5Chlorophyta (Green Algae)Chlorophytaincludes thegreen algae, which areespecially important in understanding evolution.•Some green algae areflagellatedand can move.•A common laboratory example isSpirogyra.•Many species formcolonies, where groups of cells live together and cooperate.These colonial green algae are thought to show some of theearliest steps toward multicellularity.They have features that arebetween single-celled organisms and complex multicellularorganisms.Another well-known member of this group isUlva, commonly calledsea lettuce, which is found inmarine environments.2. Quiz Algae1. QuestionWhy are algae considered plantlike?Answer Choices•They have chloroplasts filled with chlorophyll.

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Study Guide•They have roots.•They have vascular tissue composed of xylem and phloem.Correct AnswerThey have chloroplasts filled with chlorophyll.Why This Is CorrectAlgae are considered plantlike because they contain chloroplasts with chlorophyll, which allows themto perform photosynthesis. This is a key characteristic of plants.Algae donothave true roots, and they also lack vascular tissues like xylem and phloem, which arefound in higher plants.2. QuestionHow are algae subdivided into divisions?Answer Choices•by food source•by locomotion•by types of pigmentsCorrect Answerby types of pigmentsWhy This Is CorrectAlgae are divided into different groups based on the types of pigments they contain. These pigmentsaffect their color and how they capture light for photosynthesis.For example, some algae appear green, red, or brown because of differences in their photosyntheticpigments—not because of how they move or what they eat.

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Study Guide3. QuestionWhich of the following include red algae that photosynthesize using chlorophylla?Answer Choices•Chrysophyta•Pyrrophyta•RhodophytaCorrect AnswerRhodophytaWhy This Is CorrectRhodophytais the division that includes red algae. These algae contain chlorophylla, which allowsthem to carry out photosynthesis.Chrysophytaand Pyrrophyta are other algal divisions, but they do not include red algae.4. QuestionWhich of the following are the golden algae?Answer Choices•Chlorophyta•Chrysophyta•PhaeophytaCorrect AnswerChrysophytaWhy This Is Correct

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Study GuideChrysophytaare known as the golden algae because they contain pigments that give them a goldenor yellow-brown color.Chlorophyta are green algae, and Phaeophyta are brown algae, so neither of those choices is correct.5. QuestionWhich of thefollowing may be luminescent?Answer Choices•Chrysophyta•Phaeophyta•PyrrophytaCorrect AnswerPyrrophytaWhy This Is CorrectPyrrophyta(also known as dinoflagellates) may be luminescent. Some species can produce light,causing glowing effects in ocean water at night.Chrysophyta (golden algae) and Phaeophyta (brown algae) do not typically show luminescence.6. QuestionWhich of the following is the main component of the bacteriological medium called agar?Answer Choices•Chlorophyta•Pyrrophyta•Rhodophyta

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Study GuideCorrect AnswerRhodophytaWhy This Is CorrectAgar is derived fromred algae, which belong to the divisionRhodophyta. Substances extracted fromthese algae are used to make agar, a solidifying agent commonly used in bacteriological culturemedia.Chlorophyta (green algae) and Pyrrophyta (dinoflagellates) are not sources of agar.7. QuestionWhich of the following are surrounded by thick plates that give them an armored appearance?Answer Choices•Chrysophyta•Phaeophyta•PyrrophytaCorrect AnswerPyrrophytaWhy This Is CorrectPyrrophyta(dinoflagellates) are surrounded by thick cellulose plates that form an outer covering.These plates give them a distinctivearmored appearance.Chrysophyta (golden algae) and Phaeophyta (brown algae) do not have this plated, armoredstructure.8. QuestionWhich of the following compose a red tide?

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Study GuideAnswer Choices•Chlorophyta•Chrysophyta•PyrrophytaCorrect AnswerPyrrophytaWhy This Is CorrectPyrrophyta(dinoflagellates) are responsible for red tides. During rapid population growth, theseorganisms can discolor ocean water and may release toxins that affect marine life and humans.Chlorophyta (green algae) and Chrysophyta (golden algae) do not typically cause red tides.9. QuestionWhich of the following have cell walls composed of twooverlapping halves impregnated with silica?Answer Choices•Chrysophyta•Phaeophyta•PyrrophytaCorrect AnswerChrysophytaWhy This Is CorrectChrysophytainclude diatoms, which have unique cell walls made ofsilica. These walls consist oftwo overlapping halves, fitting together like a petri dish.Phaeophyta (brown algae) and Pyrrophyta (dinoflagellates) do not have silica-impregnated, two-partcell walls.

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Study Guide10. QuestionWhich of the following are known as rock weeds and kelps?Answer Choices•Chrysophyta•Phaeophyta•PyrrophytaCorrect AnswerPhaeophytaWhy This Is CorrectPhaeophytaare the brown algae, which includerock weeds and kelps. These algae are usuallylarge, multicellular, and found in marine environments, especially alongrocky coastlines.Chrysophyta (golden algae) and Pyrrophyta (dinoflagellates) are not known as rock weeds or kelps.11. QuestionWhich of the following are often sources of iodine?Answer Choices•Chrysophyta•Phaeophyta•PyrrophytaCorrect AnswerPhaeophytaWhy This Is Correct
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Document Details

University
Texas A&M University
Course
Biology
Subject
Biology

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