1-1: Cell Intro

Question 1

Unicellular Organisms

Answer 1

Living beings composed of a single cell that can perform all life processes independently. Examples include bacteria, archaea, and some protists

Question 2

Multicellular Organisms

Answer 2

Complex organisms composed of many specialized cells organized into tissues, organs, and organ systems. Examples include plants, animals, and fungi.

Question 3

Cells AS Organisms
vs
Cells IN Organisms

Answer 3

some life forms, like unicellular organisms, are complete and self-sufficient entities contained within a single cell

in multicellular organisms, cells have specific roles and functions, working together to perform tasks within tissues and organs.

Question 4

Cell Theory (4)

Answer 4

• All organisms are made up of cells,
• Cells r the fundamental unit of life,
• Cells come from preexisting cells.
• The cell is the smallest unit of life

Question 5

The endosymbiont theory:

Answer 5

All cells are thought to have evolved from a universal ancestor cell [LUCA – last universal common ancestor from 3.5 to 3.8 billion years ago].

Idea that eukaryotic cells evolved when one cell swallowed another, and they started working together. This explains the origin of mitochondria and chloroplasts in eukaryotic cells

Question 6

Why have Chloroplasts and mitochondria thought to have evolved from an endosymbiont? (3)

Answer 6

• They are surrounded by two membranes.
• Their inner membranes have structures that closely resemble certain prokaryotic cells.
• They each contain circular genomes that code for genes that are very similar to bacterial genes.

Question 7

Cells are considered the smallest unit of life, and several characteristics define them as such. Let’s list and evaluate these characteristics:

Answer 7

Cellular Organization
Metabolism
Growth and Development
Reproduction
Response to Stimuli
Homeostasis
Heredity
Evolutionary Adaptation
Energy Processing
Membrane-Bound Structure

Question 8

Bacterial and Eukaryotic Cells (Similarities)

Answer 8

• Both have plasma membranes.
• Contain genetic material (DNA or RNA).
• Engage in metabolic processes.
• Capable of growth and reproduction.
• Respond to environmental stimuli.
• Maintain homeostasis.

Question 9

Bacterial and Eukaryotic Cells (Differences)

Answer 9

Bacterial Cells:
- Lack a true nucleus.
- Have a single, circular chromosome.
- Smaller in size (1-5 micrometers).
- Cell wall made of peptidoglycan.
- Lack membrane-bound organelles.

Eukaryotic Cells:
- Have a well-defined nucleus.
- Possess multiple linear chromosomes.
- Larger in size (10-100 micrometers or more).
- Cell wall composition varies.
- Contain membrane-bound organelles.