Biology-Lab 4- Cell Structure

Prokaryotic cell

A cell that lacks a nucleus.

Cell

The smallest unit of life that can function independently.

Key Concepts

A cell is the smallest unit of life that can function independently and perform all the activities necessary for life. The cell is the basic unit of life, and all living organisms are composed of one or more cells. All cells have several features in common: -DNA: stores the genetic material -Cell membrane: surrounds the cell -Cytoplasm: watery mixture that occupies the inside of cells; all the cell contents between the nucleus (in cells that have one) and the cell membrane -Cytosol: fluid portion of the cytoplasm -RNA and proteins: molecules that play important roles in the cell -Ribosomes: structures that are the sites of protein synthesis -Small size: cells are typically between 1-100 micrometers in diameter Two main categories of cells are; -prokaryotic cells, which lack a nucleus, -eukaryotic cells, which contain membrane-bounded organelles, including a nucleus. Organisms made of prokaryotic cells include bacteria and archaea. Eukaryotic cells tend to be larger than prokaryotic cells, and organisms made of eukaryotic cells include protists, fungi, plants, and animals.

Eukaryotic cell

A cell that contains a nucleus and other membrane-bounded organelles and that tends to be larger than a prokaryotic cell.

Cytoplasm

A fluid called cytosol plus all the cell contents between the nucleus (in eukaryotic cells) and the cell membrane.

Micrograph

A photograph taken through a microscope of a magnified specimen.

What part of all cells encases the cytoplasm and forms a boundary between the cell interior and cell exterior?

Cell Membrane

In plant cells, what structure lies just outside the cell membrane and provides strength and support to the plant cell?

Cell Wall

Identify the features common to all cells. Select all that apply.

Cell membrane Cytoplasm DNA Ribosomes

What structure found in plant cells is an organelle for storing water and metabolites?

Central vacuole

Identify the features present in animal cells. Select all that apply.

Centrioles Golgi apparatus Mitochondria Nucleus Rough endoplasmic reticulum

What structure is found in plant cells but not in animal cells?

Chloroplast

What is the name of all the cell contents between the nucleus and the cell membrane?

Cytoplasm

Overview

In this simulation, you will: -View animal and plant cells under a microscope. -Identify and label basic cell structures on micrograph images. -Label cell structures on animal and plant cell diagrams.

Organelles

Membrane-bounded compartments in eukaryotic cells that carry out specialized functions.

Cell membrane

Lipid-rich bilayer that surrounds the cytoplasm and contents of a cell and forms a boundary between the cell interior and its environment.

RNA (ribonucleic acid)

Nucleic acid that is synthesized from DNA and is used at ribosomes to coordinate the synthesis of proteins.

DNA (deoxyribonucleic acid)

Nucleic acid that serves as the genetic material in all cells by encoding the information for the production of proteins and RNA.

Identify features that are present in eukaryotic cells but not in prokaryotic cells.

Nucleus and membrane-bounded organelles

Chloroplast

Organelle found in plant cells and some protist cells that carries out photosynthesis to produce sugars.

Central vacuole

Organelle found in plant cells that is a large, fluid-filled sac for storing water and metabolites.

Mitochondria

Organelle that carries out cellular respiration to produce ATP.

Nucleus

Organelle that contains the DNA and acts as the command center of the cell.

Smooth endoplasmic reticulum

Organelle that is a network of membranes and is the site of lipid synthesis and the detoxification of certain drugs and poisons.

Rough endoplasmic reticulum

Organelle that is a network of membranes studded with ribosomes and that plays a role in protein synthesis.

Golgi apparatus

Organelle that is a stack of flattened sacs where proteins are modified, processed, and packaged for different locations in the cell or for export.

Prokaryotic and eukaryotic cells compared

Other organelles and structures found in eukaryotic cells include the rough endoplasmic reticulum, smooth endoplasmic reticulum, Golgi apparatus, mitochondria, centrioles, chloroplasts, central vacuole, and cell wall.

Cell wall

Outer layer on prokaryotic, plant, fungi, and many protist cells that surrounds the cell membrane and provides support, shape, and strength to the cell.

Ribosomes

Structures composed of RNA and protein that are the sites of protein synthesis.

Before you begin

The microscope you are using has three objective lenses to magnify the image: 4X, 10X and 40X, resulting in a total magnification of 40X, 100X and 400X, respectively. When focusing on a slide, start on the lower-power objective lens. The lower the power objective, the greater the field of view. It is important to realize when visualizing tissues some views may be better than others. Therefore, you may have to move the slide around to find the best view of what you are interested in observing. To move the slide, you move the stage.

Centrioles

Two short cylinders of proteins found in animal cells that help to organize microtubules.