3  Cells

3.1 Introduction

The cell is the smallest structural and functional unit of life. In this lab, the internal and external structures of the cell are identified along with their functions. Cellular organelles, membrane structure, membrane transport, and the stages of the cell cycle and mitosis are examined. Microscopy techniques are used to observe representative cell types.

3.2 Prelab Activity 3.1 β€” Cell Structure and Function

3.2.1 Definitions

Term Definition
Cytoplasm Material inside the cell membrane but outside the nucleus
Cytosol Semi‑fluid portion of the cytoplasm
Organelles Membrane‑bound structures that perform specific functions

3.2.2 Organelle Types

Term Definition
Rough endoplasmic reticulum Protein synthesis and modification
Smooth endoplasmic reticulum Lipid synthesis and detoxification
Golgi apparatus Modifies and packages proteins
Mitochondrion Produces ATP
Lysosome Digestion of cellular material
Peroxisome Detoxifies harmful substances
Microfilaments Cytoskeletal support and movement
Microtubules Shape, transport, and cell division
Cilia Move substances across cell surface
Flagella Propel the cell
Nucleus Contains DNA
Nucleolus Produces ribosomal subunits

3.2.3 Membrane Transport

Passive transport: Movement across a membrane without energy input Active transport: Movement requiring ATP Diffusion: Movement from high to low concentration Osmosis: Diffusion of water across a membrane 

3.2.4 Cell Cycle

Cell cycle: Life cycle of a cell Interphase: Growth and DNA replication phase Mitosis: Division of nucleus 

3.2.5 Stages of Interphase

Interphase: Entire growth period G1 phase: Cell growth S phase: DNA synthesis G2 phase: Preparation for mitosis 

3.3 Prelab Activity 3.2 β€” Stages of Mitosis

Stage Events Appearance
Prophase Chromatin condenses Chromosomes visible
Metaphase Chromosomes align Line at center
Anaphase Chromatids separate Pulled apart
Telophase Nuclear membranes reform Two nuclei
Cytokinesis Cytoplasm divides Two cells

3.4 Prelab Activity 3.3 β€” Cell Identification

Number Structure
1 Nucleolus
2 Nucleus
3 Ribosome
4 Vesicle
5 Rough ER
6 Golgi apparatus
7 Cytoskeleton
8 Smooth ER
9 Mitochondrion
10 Vacuole
11 Cytosol
12 Lysosome
13 Centrosome
14 Plasma membrane

3.5 Prelab Activity 3.4 β€” Cell Membrane Structure

Label Structure
a Phospholipid bilayer
b Hydrophilic head
c Hydrophobic tail
d Integral protein
e Cholesterol
f Peripheral protein
g Glycoprotein

3.6 Prelab Activity 3.5 β€” Cell Cycle Definitions

Cytokinesis: Division of cytoplasm Interphase: Growth and DNA replication M-phase: Mitotic phase Chromosome: Condensed DNA Chromatin: DNA-protein complex 

Stages of mitosis:

Prophase Metaphase Anaphase Telophase Cytokinesis 

3.7 Lab Activity 3.2 β€” Organelles and Function

Structure Organelle Function
Plasma membrane Regulates entry and exit
Cilia Move substances
Microvilli Increase surface area
Nucleolus Makes ribosomes
Nucleus Houses DNA
Nuclear envelope Protects nucleus
Nuclear pore Material transport
Ribosome Protein synthesis
Vesicle Transport
Peroxisome Detoxification
Lysosome Digestion
Golgi apparatus Protein packaging
Mitochondrion ATP production
Rough ER Protein synthesis
Smooth ER Lipid synthesis
Centriole Cell division

3.8 Post Lab Activity 3.1 β€” Fill in the Blanks

The smallest independent unit that is alive is the cell. The region housing most genetic material is the nucleus. Most cellular machinery is in the cytoplasm. The membrane is a phospholipid bilayer with integral and peripheral proteins. 

3.9 Post Lab Activity 3.2 β€” Multiple Choice

1. Integral proteins 2. Ribosomes 3. The water 4. Ribosomes 5. Production of proteins 6. Mitochondria 7. G1 

3.10 Post Lab Activity 3.3 β€” Matching

# Answer
1 f
2 e
3 i
4 d
5 g
6 a
7 c
8 b
9 j
10 h

3.11 Post Lab Activity 3.4 β€” Crossword Answers

Across:
3 Cell nucleus
5 Plasma membrane
6 Lysosome
7 Peroxisome

Down:
1 Nucleolus
2 Centriole
4 Golgi apparatus
8 Ribosome

3.12 βœ… End of Chapter 3