Characteristics of a cell

What does molecular cell biology study?

How cells are organised and how cellular processes work

Why is cell biology considered broad?

It overlaps with genetics biochemistry microscopy medicine agriculture and evolution

Why is microscopy essential in cell biology?

Most cells and organelles are too small to see with the naked eye

What does the ! symbol mean in the handouts?

Essential information that could be examined

What does the ~ symbol mean in the handouts?

Extra context or examples that are less likely to be examined

What are the main groups of life discussed in the lecture?

Animals plants fungi protists and prokaryotes

Why can morphology be misleading in classification?

Different organisms can look similar but be evolutionarily unrelated

Why were fungi once confused with plants?

Some fungi form long filaments that look plant-like

Are fungi more closely related to plants or animals?

Animals

What are hyphae?

Long filamentous structures formed by some fungi

What are yeasts?

Single-celled fungi

Why are yeast useful model organisms?

They are simple eukaryotes that share many processes with human cells

What is Saccharomyces cerevisiae?

Bakers yeast

What is Schizosaccharomyces pombe?

Fission yeast

Why are haploid fungi useful in research?

Genetic changes are easier to study because there is only one chromosome copy

What are chloroplasts?

Plant organelles that carry out photosynthesis

What is the cell wall?

A rigid external structure outside the plasma membrane

Do animal cells have a cell wall?

No

What do animal cells have instead of a cell wall?

A plasma membrane

What is the plasma membrane?

A flexible selective barrier around the cell

What is intracellular movement?

Movement inside a cell

What is intercellular movement?

Movement between cells

What is cellular motility?

Movement of an entire cell

What is the biggest organelle in most eukaryotic cells?

The nucleus

What is an oocyte?

An egg cell

Why are oocytes large?

They contain a lot of cytoplasm

What does 10 angstrom equal?

1 nanometer

What does 1000 nanometers equal?

1 micrometer

What does 1000000 micrometers equal?

1 meter

Are viruses usually larger or smaller than cells?

Smaller

Why are cells difficult to study without microscopes?

They are usually only micrometers in size

Who introduced the term cell?

Robert Hooke

What book did Robert Hooke publish in 1665?

Micrographia

What material did Robert Hooke examine when he described cells?

Cork

Why did Hooke call them cells?

They looked like small rooms in a monastery

Was Hooke looking at living cells?

No he was mainly seeing dead cork cell walls

Who discovered bacteria using early microscopes?

Antonie van Leeuwenhoek

What did Leeuwenhoek discover?

Bacteria protists sperm cells and muscle fibres

What are the three domains of life?

Bacteria archaea and eukaryotes

Who introduced the three domain classification?

Carl Woese

What molecule was used for the three domain classification?

Ribosomal RNA

What are prokaryotes?

Cells without a true nucleus

What are eukaryotes?

Cells with a true nucleus

What does prokaryote mean?

Before nucleus

What does eukaryote mean?

True nucleus

Do prokaryotes have membrane-bound organelles?

No

Do eukaryotes have membrane-bound organelles?

Yes

Where is bacterial DNA found?

In the nucleoid

What shape is bacterial DNA usually?

Circular

What structure helps some bacteria move?

Flagellum

What are pili?

Short bacterial surface structures used for attachment or DNA exchange

What is the function of ribosomes?

Protein synthesis

What does the bacterial cell wall do?

Provides protection and shape

What is cytoplasm?

The internal fluid and contents of the cell

What is the endomembrane system?

Internal membranes that form compartments in eukaryotic cells

Why do eukaryotic cells have compartments?

To separate different cellular environments and functions

What does the nucleus contain?

DNA

What surrounds the nucleus?

The nuclear envelope

How many membranes does the nucleus have?

Two

What is the endoplasmic reticulum involved in?

Protein and lipid processing

What is the Golgi apparatus involved in?

Modifying and sorting proteins

What do mitochondria produce?

ATP

What are lysosomes involved in?

Digestion and recycling

What are peroxisomes involved in?

Metabolic reactions and breakdown of harmful compounds

What organelle is found in plants but not animals or fungi?

Chloroplast

What cell feature is found in plants fungi and bacteria but not animals?

Cell wall

What is the large plant vacuole related to?

Lysosome-like storage and degradation functions

Who proposed cell theory in 1839?

Matthias Schleiden and Theodor Schwann

What is the first idea of cell theory?

The cell is the basic unit of living things

What is the second idea of cell theory?

Cells are distinct entities and building blocks of organisms

What part of early cell theory was wrong?

The idea that cells form spontaneously

Who corrected cell theory by saying cells come from pre-existing cells?

Rudolph Virchow

What does all cells arise from pre-existing cells mean?

New cells are made by division of existing cells

Who proposed the central dogma?

Francis Crick

When was the central dogma proposed?

1958

What is the central dogma?

DNA → RNA → protein

What is transcription?

Copying DNA information into RNA

What is translation?

Using RNA information to make protein

What stores hereditary information in cells?

DNA

What molecule helps transfer genetic information from DNA to protein?

RNA

What molecules put genetic information into action?

Proteins

What is metabolism?

The biochemical reactions that keep a cell alive

Why are viruses usually not considered cells?

They lack independent metabolism and need host cells to reproduce

What are the common features of all cells?

Metabolism plasma membrane DNA RNA proteins and cell division

What is a protein made of?

Amino acids

What is the primary structure of a protein?

The amino acid sequence

What is secondary protein structure?

Local folding such as alpha helices and beta sheets

What is tertiary protein structure?

The overall three-dimensional folded shape

What is quaternary protein structure?

Multiple protein subunits assembled together

Why is protein shape important?

Shape determines function

What are hydrogen bonds in proteins?

Weak interactions important for folding

What are ionic interactions in proteins?

Interactions based on charge

What are hydrophobic interactions in proteins?

Interactions caused by avoidance of water

What are disulfide bridges?

Strong covalent bonds between parts of a protein

What is the cell cycle?

The process where cells grow duplicate contents and divide

What happens in G1 phase?

Cell growth and preparation for DNA replication

What happens in S phase?

DNA replication

What happens in G2 phase?

Further growth and preparation for division

What happens in M phase?

Mitosis and cell division

What is mitosis?

Division of the nucleus and chromosome separation