Bacteria

II Bimestrial Sixth Grade

Ms. Matta

Science Class Chapter 2 Lesson 2

Unlock the Big ?

What are bacteria?

How do bacteria get food, get energy, and reproduce?

What is the role of bacteria in Nature?

My Planet Diary“Good” Germs

Misconception: All bacteria are harmful.

• Many bacteria are harmless or even good for you! Your intestines are full of good bacteria. Some types of helpful bacteria, often called probiotics, are found in foods like yogurt, smoothies, and even cereal!

• These foods put good bacteria into your body to help fight off the harmful bacteria that can cause disease.

Vocabulary Lesson 2

• bacteria

• cytoplasm

• ribosome

• flagellum

• cellular respiration

• conjugation

• binary fission

Key Concepts• bacteria(singular bacterium): are prokaryotes,

they lack of nucleus.

• cytoplasm: contains a gel-like fluid that moves structures throughout the cell.

• ribosomes: located in the cytoplasm, tiny structures is where the proteins are produce.

• flagellum(plural flagella): A long, whiplike structure that helps a cell to move.

Bacteria Cell Structure

Generic material

Cell membrane

Cell wallRibosomes Cytoplasm

Flagellum

How do bacteria get food, energy, and reproduce?

• Bacteria get energy by either making a food or eating other organisms, and can reproduce asexually or sexually.

Obtaining Food• Some

bacteria are autotrophs, meaning they make their own food. Some capture and use the sun’s energy as plants do.

• Others such as bacteria that live deep in mud, do not use the sun’s energy. Instead, these bacteria use the energy from chemicals substances in their environment to make their food.

• Some bacteria are heterotrophs, and cannot make their own food. They must consume other organisms or the food that they make. It can consume: milk and meat.

Autotrophic bacteria

Heterotrophic bacteria

Respiration

• Like all organisms, bacteria need a constant supply of energy to carry out their functions. This energy comes from food.

• The process of breaking down food to release energy is called cellular respiration.

• The oxygen in some bacterias is a poison that kills!

ReproductionAsexual Reproduction:

Bacteria sometimes reproduce asexually by a process called binary fission, in which one cell divides to form two identical cells. To prepare for binary fission, a bacteria cell grows to almost twice its size. Then it duplicates its genetic material and splits into two separate cells.

ReproductionSexual Reproduction:

Sometimes bacteria reproduce sexually by a process called conjugation. During conjugation, one bacterium transfers some of its genetic material into another bacterium through a thin, threadlike bridge. After the transfer, the bacteria separate.

Conjugation does not increase the number of bacteria, however the bacteria is genetically different from the parent cells.

What is the Role of Bacteria in Nature?

• Bacteria are involved in oxygen and food production, in health maintenance and medicine production, and in environmental cleanup and recycling.

Videos

• Viruses: https://www.youtube.com/watch?v=UEKS4w9bfJg

• https://www.youtube.com/watch?v=cE0qdqoBFa8

• Bacteria: https://www.youtube.com/watch?v=qCn92mbWxd4

• https://www.youtube.com/watch?v=3xRttWuf3wQ