Biology: cells

Biology: Cells

-Didactic Unit for 3rd of ESO Elena Caballero MartĂ­n Aida SĂĄnchez Moro

Elena Caballero MartĂ­n y Aida SĂĄnchez Moro Didactic Unit: Cells / Materials

Session 1

Introduction to Cells 1. After watching the video, can you guess what we are made of?

Which cells could you identify?

red blood cells

liver

chromosome

ovule

organelle

neuron

spermatozoon

brain

2. Write the different levels of biological organization in the right order.

Multicellular level

Population level

Cellular level

Ecosystem level

Molecular level

Atomic level

Atomic level

Elena Caballero MartĂ­n y Aida SĂĄnchez Moro Didactic Unit: Cells / Materials 3. Match each group of cells with their definition.

Blood cells

They are unique cells of the body that are unspecialized and have the ability to develop into specialized cells for specific organs or to develop into tissues.

Skin cells

They transport oxygen throughout the body and fight infections. The three major types of cells of this group are red blood cells, white blood cells, and platelets.

Sex cells

Also called adipocytes, they are the major cell component of adipose tissue. Adipocytes contain droplets of stored fat (triglycerides) that can be used for energy.

Cancer cells

They protect the internal structures of the body from damage, prevent dehydration, act as a barrier against germs, store fat, and produce vitamins and hormones.

Stem cells

Also known as neurons, they are the basic unit of the nervous system. Nerves send signals among the brain, spinal cord, and other body organs via nerve impulses.

Nerve cells

They are reproductive cells produced in male and female gonads. In sexual reproduction, these cells unite during fertilization to form a new individual.

Fat cells

Their development can be caused by mutations that occur from factors such as chemicals, radiation, ultraviolet light, chromosome replication errors, or viral infection.

Elena Caballero MartĂ­n y Aida SĂĄnchez Moro Didactic Unit: Cells / Materials 4. Read the text and decide if the sentences are true or false, and rewrite those which are false.

The Cell Theory The three statements of the cell theory are: 1. All living beings are made up of cells.

2. Cell is the most basic unit of life.

3. All cells must come from pre-existing cells.

The first statement refers to the fact that all the life forms present on this planet are composed of one or more cells. The simplest life forms are unicellular, that is are made up on single cells; whereas the higher life forms (human beings, trees, etc.) are multicellular (composed of many cells). The second statement refers to the idea that cells can carry out all the functions required for life propagation including, reproduction, maintenance, growth, metabolism, etc. And the third statement refers to the reproduction of cells from parent cell or cells. It means that cells are born from existing cells and that's how life propagates.

a) b) c) d)

All living beings are made up of cells, except plants and trees.

Cells can carry out all the functions required for life propagation.

The simplest form of life is the atom.

Every cell is born from an exiting cell.

Elena Caballero Martín y Aida Sánchez Moro Didactic Unit: Cells / Materials

TYPES OF CELLS Session 2 As you have seen in the previous session, all living things are made of cells (including human beings). There are millions and millions of cells on Earth. But not all of them have the same structure or carry out the same life functions.

You are going to watch a video on the different types of cells and their differences. After watching the video once, try to answer these questions:

 What types of cells are there?  What do they have in common?  What is the main difference?

Watch the video again but this time pay attention to the different parts of cells and their functions. Try to match each part with their function.

FUNCTIONS PARTS Cell membrane Cell wall DNA Ribosomes Organelles Nucleus

offers support and protection. are like the organs of cells. controls what goes in and out of the cell. transfers the genetic information when making other cells. controls the cell’s functions and holds the genetic material. are tiny structures that make protein for the cell.

Elena Caballero Martín y Aida Sánchez Moro Didactic Unit: Cells / Materials

Here you have a chart with the main differences between both types:

PROKARYOTES

EUKARYOTES

NO ORGANIZED NUCLEUS

ORGANIZED NUCLEUS

NO MEMBRANE-BOUND ORGANELLES

MEMBRANE-BOUND ORGANELLES

SMALLER CELLS

LARGER CELLS

ALWAYS UNICELLULAR

UNICELLULAR OR MULTICELLULAR

As you see, organisms can have a single cell (prokaryote or eukaryote) or more than one. And how can we classify organisms? Well, the most common classification is the five kingdom classification. Let’s find out about it:

THE FIVE KINGDOM OF LIFE GLOSSARY protists – protoctistas algae – algas motionless – sin movimiento fungi – hongos mold – moho yeast – levadura sturdy – robusto, fuerte cellulose – celulosa crop – cultivo nervous system –sistema nervioso (in)vertabrate – (in)vertebrado mammal – mamífero

Every living creature on Earth belongs to a kingdom.

Scientists debate how many kingdoms there are, but most agree there are five. Here is how the five kingdoms are organized.

Monera are single-celled organisms that don’t have a nucleus. Bacteria make up the entire kingdom. There are more forms of bacteria than any other organism on Earth.

Some bacteria are beneficial to us, such as the ones found in yogurt. Others can cause us to get sick.

Protists are mostly single-celled organisms that have a nucleus. They usually live in water. Some protists move around, while others stay in one place. Examples of protists include some algae, paramecium and amoeba.

Fungi are usually motionless organisms that absorb nutrients for survival. There organisms may be unicellular or multicellular. They include mushrooms, molds and yeasts.

Plants contain chlorophyll, a green pigment necessary for photosynthesis, a process in which plants convert energy from sunlight into food. Their cell walls are made sturdy by a material called cellulose, and they are fixed in one place. Plants are divided into two groups: flower and fruit-producing plants and those that don’t produce flowers or fruits.

They include garden flowers, agricultural crops and grasses among others.

Animals are the most complex organisms on Earth. Animals are multi-celled organisms, eat food for survival, and have nervous systems. They are divided into vertebrates and invertebrates and include mammals, amphibians, reptiles, birds and fish.

Elena Caballero MartĂ­n y Aida SĂĄnchez Moro Didactic Unit: Cells / Materials

1. Answer the questions: 1) 2) 3) 4)

Which of these organisms will be made up by prokaryotic cells?

Which will be made up by eukaryotic cells?

How do plants produce food? What about animals?

After reading the text, can you recognise and classify these organisms in the right kingdom?

2. As you have read in the text, not all bacteria all bad. We have a large concentration of bacteria in our body and we depend heavily on them for health. Look up for some information on the Internet and write a short text on how bacteria help us. ...................................................................................... ...................................................................................... ...................................................................................... ...................................................................................... ...................................................................................... ...................................................................................... ...................................................................................... ...................................................................................... ......................................................................................

Elena Caballero MartĂ­n y Aida SĂĄnchez Moro Didactic Unit: Cells / Materials

Session 3 Final task: research In groups of 5 people, you have to prepare a PowerPoint Presentation about your research.

Each group has to choose one topic: -

Structure of the animal cell Structure of the plant cell Cell reproduction: Mitosis Cell reproduction: Meiosis Viruses Steps for the research: 1. Look for information online.

2. Analyze and select the information you want to include.

3. Organize the information corresponding to the different slides and adapt it to your discourse.

4. Rehearse the presentation to make sure that it fits in 15 minutes.

-

The presentation has to be 15 minutes long.

All the members of the group have to speak.

The slides can contain text, images or both.

You can also include videos of maximum 3 minutes.

You can use a scrip as a guide to speak in your presentation, but you are not allowed to read.

Once you finish, you have to upload the PowerPoint presentation to the class blog, so that it will be available for the rest of your classmates.