Biology Chapter: Cell Structure and Function

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Questions and Answers

What structural feature of cell walls enhances diffusion?

Thinness of a single cell layer (correct)

Thickness of multiple layers

Presence of a nucleus

Having many components other than cells

What is the primary function of red blood cells?

To generate energy molecules

To transport oxygen to cells (correct)

To produce hormones

To filter waste products

How does the biconcave shape of red blood cells contribute to their function?

Increases surface area for absorbing oxygen (correct)

Reduces overall surface area for gas uptake

Facilitates movement through blood vessels

Increases cell rigidity to improve transport

What is the function of haemoglobin?

A pigment that binds to oxygen for transport Signup and view all the answers

In the body tissues, what process occurs with oxyhaemoglobin?

The haemoglobin releases oxygen Signup and view all the answers

What is the primary direction of water movement during osmosis?

From an area of higher water concentration to an area of lower water concentration Signup and view all the answers

What is the relationship between the concentration gradient and the rate of diffusion?

A larger concentration gradient results in a faster rate of diffusion Signup and view all the answers

Which process describes the movement of substances against a concentration gradient?

Active transport Signup and view all the answers

What is the main function of the lungs in gas exchange?

To transfer oxygen to the blood and remove carbon dioxide Signup and view all the answers

What are the tiny air sacs in the lungs where gas exchange occurs?

Alveoli Signup and view all the answers

What is the first step of blood flow within the heart?

Blood flows into the atria Signup and view all the answers

Following the filling of the atria, what action does the heart take next?

The atria contract, pushing blood into the ventricles Signup and view all the answers

What is the primary function of ventricles in the heart?

To contract and force blood into arteries Signup and view all the answers

Given that an experiment used a potato in pure water and a sugar solution, which of them resulted in absorption?

The potato in the water absorbed water Signup and view all the answers

Which type of blood vessel carries blood away from the heart?

Arteries Signup and view all the answers

What is the role of capillaries in the circulatory system?

To facilitate the exchange of materials at the tissues Signup and view all the answers

What is a key characteristic of a partially permeable membrane?

It allows only tiny molecules, such as water, to pass through. Signup and view all the answers

What is the function of coronary arteries?

To surround the heart and provide it with its own oxygenated blood Signup and view all the answers

Which of the following best describes veins?

They carry blood toward the heart Signup and view all the answers

During osmosis, how does water move across a partially permeable membrane?

Water molecules pass through the membrane in both directions with a net flow into the region with fewer water molecules. Signup and view all the answers

What characteristic of capillary walls allows for diffusion of substances?

They have thin walls that are permeable Signup and view all the answers

What causes the net flow of water during osmosis?

The difference in water molecule concentration on either side of the membrane. Signup and view all the answers

How does the movement of water in osmosis affect a sugar solution?

It makes the sugar solution less concentrated. Signup and view all the answers

What initiates the cycle of blood flow through the heart?

The initial contraction of the ventricles Signup and view all the answers

After arteries branch into capillaries, what is the next step in the flow of blood?

Blood flows back to the heart through veins. Signup and view all the answers

What is the primary driving force behind the movement of molecules in osmosis?

The random kinetic energy of the molecules. Signup and view all the answers

If the water concentration is lower on the left side of the membrane than the right, what will occur during osmosis?

Water will flow from right to left until equilibrium. Signup and view all the answers

What characteristic of osmosis aligns with being a passive process?

It does not require energy input from the cell. Signup and view all the answers

Which of the following best describes the role of a partially permeable membrane in osmosis?

It provides a barrier that only allows specific molecules to pass through. Signup and view all the answers

During which stage of cell division does DNA replication occur?

Mitosis Signup and view all the answers

What is the primary function of sub-cellular structures such as mitochondria during cell growth?

To increase the efficiency of cellular processes Signup and view all the answers

What is a key characteristic of chromosomes immediately after the duplication phase?

They are X-shaped with identical arms Signup and view all the answers

Which process directly results in the formation of two identical daughter cells?

Cytokinesis Signup and view all the answers

What is a unique property of embryonic stem cells?

They can turn into any type of cell in the body Signup and view all the answers

How can stem cells be used in therapeutic cloning?

To produce cells that match a patient's genetic information. Signup and view all the answers

Where are stem cells typically found in plants?

In the meristems throughout the plant's life Signup and view all the answers

What is the role of a partially permeable membrane in osmosis?

It allows the movement of water but not all solutes Signup and view all the answers

Which of the following is the main objective of using stem cells to treat patients with diabetes?

To produce insulin-producing cells Signup and view all the answers

Study Notes

Cell Cycle (Mitosis)

Cell cycle is the life cycle of the cell
Cycle includes growth, DNA replication, and mitosis
Stage 1: DNA replication and cell growth

Duplication

Chromosomes are duplicated
Forms shaped chromosomes

Division (Cytokinesis)

The DNA is the same
Two identical daughter cells are formed

Stem Cells

Stem cells can become any type of cell
Found in bone marrow
Can generate identical cells in a lab
Used in medicine for research to cure diseases
Replacement of faulty cells is a use case, for example cells producing for diabetes treatment
Can create identical plants as well

Osmosis

Movement of water molecules across a partially permeable membrane
From higher concentration to lower concentration of water
Very small holes in membrane for molecules (water), with small ones passing through.
Bigger molecules cannot pass through
Water molecules move randomly all the time
More water molecules on one side, than the other creates a steady net flow into the region with fewer molecules to even things up.
Movement of water molecules from a region with higher concentration of water towards an area of lower concentration
Similar to diffusion but only for water.

Osmosis Experiment

Experiment using potato, pure water, and a sucrose solution
Potatoes placed in solutions demonstrate absorption to even out water concentrations.

Diffusion

Spread out of particles from a higher concentration area to a lower concentration area
The larger the concentration difference the faster the diffusion

Active Transport

Substances move against the concentration gradient
Energy is needed to transport substances from an area of lower concentration towards higher concentration

Gas Exchange

Lungs are responsible for gas exchange
The job of the lungs are moving oxygen into the blood and removing waste carbon dioxide
Lungs are full of small sacs called alveoli for efficient gas exchange

Circulatory System

Blood flows into two atria from the vena cava and the pulmonary vein
Atria contract pushing blood into the ventricles
Ventricles contract sending blood to the pulmonary artery and aorta
Blood flows to the organs via the arteries and back to the heart via the veins
This cycle continues constantly

Blood Vessels

Arteries carry blood away from the heart
Capillaries exchange materials with tissues
Veins carry blood to the heart
Capillaries are small and permeable for efficient material transfer
Blood vessels have walls that are only one cell thick to increase the rate of diffusion which reduces the distance.

Blood Adaptations

Red blood cells carry oxygen
Shape is biconcave allowing large surface area for oxygen absorption
No nucleus to increase space to carry oxygen
Contains haemoglobin which binds to oxygen in lungs and releases it in the tissues

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Description

This quiz covers key concepts in biology related to cell structure, blood function, and gas exchange. Test your knowledge on how structural features of cells enhance diffusion and the primary roles of red blood cells and lungs in the body. Ideal for students studying cell biology and human physiology.