Lecture 1 Kine 2011

Which of the following best defines life in the context of cell biology?

• All life forms are multicellular

• Life is defined by the presence of organelles

• Some organisms are unicellular, while most (including humans) are multicellular

• Life only exists in eukaryotes

Multicellularity means that cells differ in:

• Only size

• Function, structure, shape, contents, number, and organization

• Only their organelles

• None of the above

Theodor Schwann’s contribution to biology was the idea that:

• The nucleus is the brain of the cell

• Cells are made of organelles

• The cell is the smallest unit that carries out life processes

• All organisms are multicellular

Approximately how many different cell types exist in the human body?

• ~20

• ~200

• ~2,000

• ~2 million

The estimated total number of human cells is about:

• 3 million

• 30 billion

• 30 trillion

• 3 quadrillion

Which cell type alone accounts for ~2–3 trillion cells in the human body?

• Neurons

• White blood cells

• Red blood cells

• Muscle cells

Which three structures are present in all eukaryotic cells?

• Plasma membrane, ribosomes, lysosomes

• Plasma membrane, cytosol, nucleus

• Cytoskeleton, Golgi, mitochondria

• Endoplasmic reticulum, nucleus, vesicles

The plasma membrane consists of:

• Proteins only

• Cholesterol only

• A phospholipid bilayer with embedded proteins

• Carbohydrates only

What happens if the plasma membrane loses integrity (develops holes)?

• The cell continues to function normally

• The nucleus repairs itself

• The cell dies

• The cell creates a new membrane instantly

The nucleus is surrounded by:

• A) A single membrane

• B) A double membrane with pores

• C) A lipid monolayer

• D) No membrane at all