High Marks: Regents Living Environment Made Easy is clear, easy to understand, and teaches the students exactly what they need for the Regents exam. The book has sample questions (from the living environment regents) with solutions to give the students practice for these exams. The homework questions are also from living environment regents exams.

Here are sample pages from High Marks: Regents Living Environment Made Easyby Sharon H. Welcher.

CELLS

Living things (organisms) are made up of one or more cells. You can see cells using a compound light microscope. Each cell carries out the life processes and all the cells work together in a coordinated manner.

Look at the picture of the cell. The cytoplasm is the jellylike substance inside the cell, surrounded by the cell membrane. The cytoplasm transports (carries) material through the cell. Many chemical reactions take place in the cytoplasm.

Look again at the picture of the cell. The structures (examples: nucleus, ribosomes, mitochondria) that are inside the cell are called organelles.

Organelles

Organelles are structures (examples: nucleus, ribosomes, vacuoles) that are inside the cell. Each organelle (examples: nucleus, ribosomes) carries out a specific life function (see below). All organelles together do all life functions; all life functions (examples respiration, synthesis, nutrition) together are called metabolism.

Cell membrane surrounds the cell. Cell membrane is made mostly of fats (lipids) and some proteins. The cell membrane controls (regulates) which materials (or how much of a material, example how much water) enters the cell or leaves the cell; you will learn about this later. The cell membrane lets digested food (example, simple sugar) enter the cell. The cell membrane lets wastes leave the cell (waste disposal).

Nucleus is the control center; it controls all life processes (metabolism). The nucleus stores genetic information (information storage); information in the nucleus directs protein synthesis (the synthesis of proteins (joining together of smaller molecules to form proteins (large molecules)).

Vacuoles storage sacs that are inside the cytoplasm. Some vacuoles store food and digest food; other vacuoles store water and get rid of excess (too much) water and other vacuoles store wastes. Vacuoles can store different materials, such as food, water, or waste.

Mitochondria are called the powerhouse of the cell. Mitochondria are the place where cellular respiration takes place. Mitochondria contain enzymes that take the energy out of food and produce energy in the form of ATP. Cells that need more energy (example muscle cells) have more mitochondria to produce more energy (in the form of ATP).

Ribosomes site (place) of protein synthesis (place where protein is made). Some ribosomes are attached to membranes; other ribosomes are floating in the cytoplasm.

Chloroplasts are only in plants (and some one celled organisms) but not in animals. Plants have chloroplasts (contain chlorophyll) and can make their own food in the presence of light (when there is light). When plants make their own food (glucose) in the presence of light, it is called photosynthesis.

Cell walls are found in plant cells and not in animal cells. Cell walls are outside the cell membrane and are made of a hard, nonliving material (cellulose). Cell walls support the plant.

Organelles work together: You know organelles are structures (example, nucleus) inside the cell. These organelles interact (work together) to maintain a balanced internal environment (homeostasis).

Examples:

1. The nucleus and ribosomes are interrelated. The nucleus is the control center; it directs the cell what to do and tells the ribosome what protein to make. Ribosome makes proteins (protein synthesis) by joining together (synthesis) amino acids to form proteins.

2. Mitochondria and ribosomes interact. Mitochondria contain

enzymes that take the energy out of food and produce energy in the form of ATP. Ribosomes use energy in the form of ATP to make protein.

3. Cell membrane and ribosomes interact. Cell membrane lets amino acids enter the cell Ribosomes use the amino acids as building blocks (synthesis) to make protein.

Organelles, cells, tissues, organs, and organ systems work together to maintain homeostasis (constant internal environment).

Organelles

together make up

Cells

combine to form

Tissues

combine to form

Organs

combine to form

Organ Systems

together make up

Organism

There are two bar graphs below, one bar graph of a plant cell and

one bar graph of an animal cell. Look at the bar graphs (a bar graph

uses bars ).

On the vertical axis is percent cell mass (example, mitochondria make up what percentage of the cell). You can tell that cell 1 is a plant cell because it has chloroplasts and a cell wall. Chloroplasts and cell wall are only in plants and not in animals. Look at the top of the bar for chloroplasts; the student draws a dotted line to the vertical axis (see Cell 1). You see the dotted line is a little above 10% but less than 20%, therefore the chloroplasts are about 12% of the cell mass (material).

Look at cell 2. Cell 2 has no (zero) chloroplasts and no cell wall (there is no bar above the word chloroplasts and no bar above the word cell wall). Cell 2 is an animal cell.

Practice Questions and Solutions

Question: The diagram below represents two cells, X and Y.

Which statement is correct concerning the structure labeled A?

(1) It aids in the removal of metabolic wastes in both cell X and cell Y.

(2) It is involved in cell communication in cell X but not in cell Y.

(3) It prevents the absorption of CO₂ in cell X and O₂ in cell Y.

(4) It represents the cell wall in cell X and the cell membrane in cell Y.

Solution: The structure labeled A is the cell membrane. The cell membrane lets wastes leave the cell which means the cell membrane helps the cell remove (get rid of) wastes both from animal cells (cell X) and plant cells (cell Y).

Answer 1

X___________________

Y___________________

Z___________________

Solution:

X ribosome

Y mitochondrion (mitochondria)

Z nucleus

Question: An organelle that releases energy for metabolic activity in a nerve cell is the

(1) chloroplast (2) ribosome (3) mitochondrion (4) vacuole

Solution: Mitochondria contain enzymes that take energy out of food and produce (release) energy in the form of ATP. Answer 3

Now Do Homework Questions #9-23, pages 42-44.

Chap. 1:8 Similarities/Differences High Marks: Regents Living Environment Made Easy

Chapter 2: Homeostasis (Dynamic Equilibrium)

You will learn in the chapter that biochemical processes of photosynthesis, respiration, enzymes, feedback, immune system, and regulation (by using hormones and nerves) help to maintain homeostasis.

Organisms (living things) need energy and raw materials (example, oxygen) to live (survive). Photosynthesis and cellular respiration are biochemical processes (see below) that produce energy; energy is needed for obtaining (getting) raw materials (example water and minerals in plants), for active transport (example water goes from areas of less concentration of water to areas of more concentration of water), for changing small molecules to large molecules, for eliminating waste, etc.

Photosynthesis Plants and algae carry on photosynthesis. In photosynthesis, in the presence of sunlight, plants take in carbon dioxide (CO₂) and water (H₂O) and produce glucose (a single sugar) and oxygen (O₂). Glucose provides energy for life processes (examples digestion, respiration, transport).

Plants and algae carry on photosynthesis, making their own food (glucose, a simple sugar); plants and algae are called autotrophs (autotrophic nutrition) because they make their own food.

Look at the leaf diagram below. There are openings in the leaf called stomates. Carbon dioxide enters (goes into) the leaf through the stomates (openings) and oxygen goes out (gas exchange, meaning exchange of gases, carbon dioxide (gas) goes in and oxygen goes out). The guard cells that surround the openings regulate the amount of carbon dioxide going in and oxygen and water vapor going out.

You learned the chloroplasts in the cells of the plant leaf and in one-celled organisms such as euglena are the site (place) of photosynthesis. Photosynthesis takes place in the chloroplasts. The chloroplasts have a green pigment called chlorophyll.

The chlorophyll takes in the sun’s (light) energy, the roots take in water which goes up the stem and to the leaf, and the leaf takes in carbon dioxide (see figure of tree); this produces glucose (simple sugar) and oxygen (see equation below). A specific enzyme is used in photosynthesis. An enzyme (biological catalyst) affects the rate of a chemical reaction, but the enzyme is not used up in the reaction.

Sun (light) energy

carbon dioxide 6 CO₂

water

6 H₂O

enzyme

glucose

C₆H₁₂O₆

oxygen

6 O₂

The process of photosynthesis uses solar energy (sun’s energy) to combine carbon dioxide and water into glucose (which has chemical bond energy) and oxygen; oxygen is given off to the environment (see equation above). Chemical bond energy (example, chemical bond energy in glucose) provides energy for life activities (life processes), such as digestion, transport, and growth.

In photosynthesis, glucose is produced. Glucose (C₆H₁₂O₆) is an organic molecule because it has both C (carbon) and H (hydrogen). Water (H₂O) and carbon dioxide (CO₂) are inorganic molecules because they do not have both C and H.

Note: When there is very little sunlight (example, far down in the ocean), very little photosynthesis takes place in plants and algae. Also, the amount of photosynthesis depends on the c olor of the light. In the presence of red light or blue light, plants can easily carry on photosynthesis; in green light, very little photosynthesis takes place.

Note: When there are more algae or plants in a lake or ocean, more photosynthesis takes place and more glucose and oxygen are produced.

Question: The diagram below represents a biological process.

Which set of molecules is best represented by letters A and B?

(1) A: oxygen and water

(2) A: glucose

(3) A: carbon dioxide and water

(4) A: glucose

B: glucose

B: carbon dioxide and water

B: glucose

B: oxygen and water

Solution: You learned organic molecules have both C and H (example glucose, C₆H₁₂O₆). Inorganic molecules do not have both C and H (examples carbon dioxide CO₂ and water H₂O).

You learned in the process (biological) of photosynthesis, carbon dioxide and water (both inorganic molecules) produce glucose (organic molecules).