Unit 2 Evolution Lesson 1 Genetic Change and Traits

Introduction to The Characteristics Of Cells Objective(s): I can list the components of the animal and plant cell and specify their functions.

Introduction to The Characteristics Of Cells A cell is the smallest functional and structural unit of all living organisms. An organism is any living thing that carries out its own life processes. Robert Hooke was the first to describe cells. He looked at the bark of a cork tree under a microscope.

Recall: Cell Theory The cell theory lists three basic characteristics of all cells and organisms. All organisms are made up of one or more cells. The cell is the basic unit of all organisms. All cells come from existing cells

The Cell Theory Organisms made up of just one cell are called unicellular organisms. The single cell must carry out all of the organism’s life functions. Organisms made up of more than one cell are called multicellular organisms. The cells of multicellular organisms have specialized functions.

What are the two types of cells? Prokaryotes are single-celled organisms that do not have a nucleus or membrane-bound organelles. Prokaryotes’ DNA is in the cytoplasm. They have organelles without cell membranes called ribosomes. Some have hairlike structures called flagella that help them move.

What are the two types of cells? Eukaryotes are organisms made up of cells that contain DNA in a nucleus, membrane-bound organelles, and ribosomes. Animals, plants, protists, and fungi are eukaryotes. Most eukaryotes are multicellular but some are unicellular.

What parts do all cells have in common? All cells have some structures in common. A cell membrane is a protective layer that covers a cell’s surface and controls materials moving into and out of the cell. The cytoplasm is the region inside the cell that includes the fluid and all the organelles except for the nucleus.

What parts do all cells have in common? An organelle is a small body in the cytoplasm that is specialized to perform a specific function. The nucleus is a membrane-bound organelle that contains DNA. DNA, or deoxyribonucleic acid, is genetic material that provides instructions for all cell processes.

What are the characteristics of eukaryotic cells? Eukaryotic cells differ from each other depending on their structure and function. Structure is the arrangement of parts. Function is the activity the parts carry out. All eukaryotic cells have a nucleus, membrane- bound organelles, and parts that protect and support the cell.

The cell membrane protects the cell and regulates what enters and leaves the cell. Throughout the cytoplasm of eukaryotic cells is a cytoskeleton, or network of protein filaments that gives shape and support to cells. The cytoskeleton also helps in cell division and in movement. The nucleus is an organelle that contains the cell’s genetic material or DNA. Instructions for making proteins are stored in DNA and sent out of the nucleus through pores in the nuclear membrane.

Cellular respiration is the process by which cells get energy by breaking down food. Mitochondrion is an organelle where cellular respiration occurs. Mitochondria have their own DNA and two membranes. Ribosomes are organelles that make proteins by putting together chains of amino acids. Ribosomes are not enclosed in a membrane. Some ribosomes are free, and others are attached to an organelle called the endoplasmic reticulum.

The endoplasmic reticulum, or ER, assists in the production, processing, and transport of proteins and in the production of lipids. Rough ER has ribosomes attached to its membrane. Smooth ER makes lipids and breaks down toxins. The Golgi complex is a system of flattened membrane sacs. It packages and distributes materials in a cell. Lipids and proteins from the ER are delivered to the Golgi complex to be modified for different jobs. Vesicles of pinched-off Golgi complex membrane carry products out of the cell or to other parts of the cell.

What additional part is found in animal cells? Lysosomes are organelles in animal cells that contain digestive enzymes. These enzymes break down damaged organelles, waste material, and foreign invaders in the cell. Some of these materials are collected in vacuoles. A lysosome attaches to the vacuole and releases the digestive enzymes inside.

What additional parts are found in plant cells? In plants, the cell wall is a rigid structure that surrounds the cell membrane, providing support and protection to the cell. Some fungi, archaea, bacteria, and protists also have cell walls. A vacuole is a fluid-filled vesicle found in the cells of most animals, plants, and fungi. A vacuole may contain enzymes, nutrients, water, or wastes. Plant cells have large central vacuoles that store water and help support the cell.

What additional parts are found in plant cells? A chloroplast is an organelle where photosynthesis occurs. Photosynthesis is the process by which cells use sunlight, carbon dioxide, and water to make sugar and oxygen. Chloroplasts are green because of green pigment called chlorophyll, which absorbs solar energy.

Objective(s) 2) I can explain what DNA is and how does it work.

Task 2 Watch the following Stated Clearly Video-What is DNA and How Does it Work Link: https://youtu.be/zwibgNGe4aY b) Take notes while watching the video.

Cracking the Code What is DNA? DNA Structure and Function Cracking the Code What is DNA? The genetic material in cells is contained in a molecule called deoxyribonucleic acid, or DNA. Scientists describe DNA as containing a code. A code is a set of rules and symbols used to carry information. To understand how DNA functions, you first need to learn about the structure of the DNA molecule. Copyright © Houghton Mifflin Harcourt Publishing Company 22

Unit 2 Lesson 6 DNA Structure and Function How was DNA discovered? Many scientists from all over the world contributed to our understanding of DNA. Some scientists discovered the chemicals that make up DNA, and others learned how these chemicals fit together. Still others determined the three-dimensional structure of the DNA molecule. Copyright © Houghton Mifflin Harcourt Publishing Company 23

Unraveling DNA What does DNA look like? Unit 2 Lesson 6 DNA Structure and Function Unraveling DNA What does DNA look like? Experiments and imaging techniques have helped scientists to infer the shape of DNA. The structure of DNA is a twisted ladder shape called a double helix. Copyright © Houghton Mifflin Harcourt Publishing Company 24

Unit 2 Lesson 6 DNA Structure and Function What does DNA look like? The two sides of the ladder are made of sugars and phosphate groups. The rungs of the ladder are made of pairs of bases. Copyright © Houghton Mifflin Harcourt Publishing Company 25

Unit 2 Lesson 6 DNA Structure and Function What does DNA look like? A base, a sugar, and a phosphate group make a building block of DNA called a nucleotide. There are four different nucleotides in DNA. Copyright © Houghton Mifflin Harcourt Publishing Company 26

Unit 2 Lesson 6 DNA Structure and Function What does DNA look like? The bases in nucleotides are paired, or complementary. Adenine always pairs with thymine (A-T). Cytosine always pairs with guanine (C-G). The order of the nucleotides in DNA is a code that carries information. Copyright © Houghton Mifflin Harcourt Publishing Company 27

The bases in nucleotides are paired, or complementary.