6 Oct Unit 2 Study Guide

Describe the structure of the cell membrane.

The cell membrane is a thin flexible layer made mostly of two layers of phospholipids with proteins in it. It surrounds and protects the cell.

Why is the cell membrane called the "gatekeeper" of the cell?

The cell membrane controls what substances can enter and leave the cell.

What does selectively permeable mean?

Selectively permeable means the cell membrane allows some substances to pass through while blocking others.

What are some functions of the cell membrane?

The cell membrane protects the cell controls what enters and leaves the cell helps cells communicate and helps maintain a stable environment inside the cell.

How does the cell membrane help maintain homeostasis?

It controls what enters and leaves the cell so the conditions inside the cell stay balanced and stable.

What does it mean for molecules to move with the concentration gradient?

Molecules move from an area of high concentration to an area of low concentration.

What does it mean for molecules to move against the concentration gradient?

Molecules move from an area of low concentration to an area of high concentration. This requires energy.

What is passive transport?

Passive transport is the movement of substances across the cell membrane without using cellular energy. Substances usually move from high concentration to low concentration.

What are two examples of passive transport?

Diffusion and osmosis.

What is diffusion?

Diffusion is the movement of molecules from an area of high concentration to an area of low concentration.

What is osmosis?

Osmosis is the movement of water across a selectively permeable membrane from an area with more water to an area with less water.

What is the difference between diffusion and osmosis?

Diffusion is the movement of particles from high to low concentration while osmosis specifically describes the movement of water across a membrane.

What is a real-life example of diffusion?

The smell of perfume spreading throughout a room is diffusion because the perfume particles move from an area of high concentration to areas of lower concentration.

What is a real-life example of osmosis?

A raisin placed in water swells because water moves through its outer membrane and into the raisin.

What is active transport?

Active transport moves substances across the cell membrane using energy. It can move substances from low concentration to high concentration.

Does active transport require energy?

Yes. Active transport requires cellular energy usually in the form of ATP.

What are two examples of active transport?

Endocytosis and exocytosis.

What is endocytosis?

Endocytosis happens when the cell membrane surrounds a substance and brings it into the cell inside a small sac called a vesicle.

What is exocytosis?

Exocytosis happens when a vesicle joins with the cell membrane and releases substances outside the cell.

What is a real-life analogy for endocytosis?

Endocytosis is like bringing groceries into your house because materials are being brought inside.

What is a real-life analogy for exocytosis?

Exocytosis is like taking the trash out of your house because materials are being moved outside.

What is the chemical equation for photosynthesis?

6CO2 + 6H2O + light energy → C6H12O6 + 6O2

What is the chemical equation for cellular respiration?

C6H12O6 + 6O2 → 6CO2 + 6H2O + ATP energy

How are the equations for photosynthesis and cellular respiration related?

They are almost opposites. The products of photosynthesis are used as reactants in cellular respiration and the products of cellular respiration are used in photosynthesis.

What are the reactants of photosynthesis?

Carbon dioxide water and light energy.

What are the reactants of cellular respiration?

Glucose and oxygen.

What are the products of photosynthesis?

Glucose and oxygen.

What are the products of cellular respiration?

Carbon dioxide water and ATP energy.

Why can plants survive without animals but animals cannot survive without plants?

Plants can make their own food through photosynthesis. Animals cannot make their own food and depend directly or indirectly on plants for food and oxygen.

What organelle is necessary for photosynthesis?

The chloroplast.

What pigment is found in chloroplasts?

Chlorophyll.

What does chlorophyll do?

Chlorophyll absorbs light energy from the Sun for photosynthesis.

What organelle is necessary for cellular respiration?

The mitochondrion or mitochondria.

What is the main job of the mitochondria?

Mitochondria perform cellular respiration and produce ATP energy for the cell.

What types of animal cells have many mitochondria?

Muscle cells have many mitochondria because they need a lot of energy to contract and move.

How is cell transport involved in photosynthesis?

Carbon dioxide enters plant cells mainly by diffusion and water moves into cells by osmosis. These materials are then used for photosynthesis.

How is cell transport involved in cellular respiration?

Oxygen can enter cells by diffusion and carbon dioxide can leave cells by diffusion. Cells use oxygen and glucose during cellular respiration to produce ATP energy.

Which types of cell transport do not require energy?

Passive transport including diffusion and osmosis does not require cellular energy.

Which types of cell transport require energy?

Active transport including endocytosis and exocytosis requires cellular energy.

What weather conditions help a plant perform photosynthesis efficiently?

Sunny conditions with enough water and moderate temperatures usually help plants perform photosynthesis efficiently.

Why does sunlight help photosynthesis?

Plants use light energy from the Sun to make glucose during photosynthesis.

Why is water important for photosynthesis?

Water is one of the reactants plants need to make glucose during photosynthesis.

What is the main purpose of photosynthesis?

To capture light energy and store it as chemical energy in glucose.

What is the main purpose of cellular respiration?

To break down glucose and release energy that the cell can use as ATP.

What is ATP?

ATP is a molecule that stores and provides usable energy for cells.

Photosynthesis mainly occurs in what type of organisms?

Plants algae and some bacteria.

Cellular respiration occurs in what types of organisms?

Both plants and animals perform cellular respiration.

Do plants perform cellular respiration?

Yes. Plants perform both photosynthesis and cellular respiration.

High concentration means what?

There are many particles in a certain area.

Low concentration means what?

There are fewer particles in a certain area.