Cell Biology Basics

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Questions and Answers

What is the primary function of actin filaments?

Facilitate communication between neurons

Aid movement by attaching to motor molecules (correct)

Provide structural support to tissues

Form a protective barrier against pathogens

Which type of muscle tissue is responsible for controlling the beating of the heart?

Cardiac muscle (correct)

Epithelial tissue

Skeletal muscle

Smooth muscle

What characteristic of epithelial tissues is emphasized in the provided content?

Ability to conduct electrical impulses

Production of connective tissues

High rate of division in skin (correct)

High elasticity and flexibility

What is the role of glial cells in the nervous system?

Providing support and protection to neurons Signup and view all the answers

Which of the following correctly describes microtubules?

They are 7nm in diameter and can form a mesh. Signup and view all the answers

What characterizes the structure of a phospholipid?

It has three main structural units. Signup and view all the answers

Which statement best describes the role of cholesterol in the cell membrane?

It maintains membrane fluidity. Signup and view all the answers

What is a primary function of glycolipids and glycoproteins in the cell membrane?

They are crucial for cell recognition. Signup and view all the answers

Which types of proteins are included as integral proteins in the cell membrane?

Channel, carrier, and recognition proteins. Signup and view all the answers

Which statement accurately describes the permeability of the cell membrane?

It is selectively permeable, allowing some molecules to pass freely. Signup and view all the answers

What is the primary function of the plasma membrane?

Barrier and transport Signup and view all the answers

Which of the following structures is responsible for sorting and packaging proteins?

Golgi Apparatus Signup and view all the answers

What is one significant difference between eukaryotic and prokaryotic ribosomes?

The sedimentation coefficient Signup and view all the answers

What unique feature distinguishes mitochondria from other organelles?

Possession of its own genome Signup and view all the answers

Which component of DNA is classified as a purine?

Adenine Signup and view all the answers

How do chloroplasts primarily generate energy for the cell?

By using light energy Signup and view all the answers

What is the main role of lysosomes in a cell?

Breaking down foreign particles Signup and view all the answers

Which organelle is primarily associated with the production of ATP?

Chloroplasts Signup and view all the answers

Study Notes

Prokaryotes

Lack membrane-bound nucleus.
Include archaea and bacteria.

Plasma Membrane

Acts as a barrier between the cell and its surroundings.
Important for transport of molecules in and out of the cell.
Plays a role in cell signaling and recognition.

DNA

Deoxyribose nucleic acid.
Contains nitrogenous bases, which can be purines or pyrimidines.

Endoplasmic Reticulum (ER)

A continuous folding of the nuclear membrane.
Rough ER is studded with ribosomes.
Involved in protein folding, modification, and transport.
Smooth ER can form lipids.

Ribosomes

Made of rRNA (ribosomal RNA).
Both eukaryotic and prokaryotic ribosomes have one large and one small subunit.
Differentiated by the sedimentation coefficient (S), which measures how fast they move in a centrifuge.

Golgi Apparatus

The "shipping center" of the cell.
Sorts, packages, and distributes proteins.
Secretes vesicles, including lysosomes.

Lysosomes

Created by the Golgi apparatus.
Contain hydrolytic enzymes.
Break down foreign particles or unneeded parts of the cell.

Mitochondria

The "powerhouse" of the cell.
Energy gradient across inner and outer membrane is used to produce ATP.
Cristae and matrix provide a large surface area for "respiration".
Number of mitochondria per cell can vary.
Contains its own circular genome, similar to prokaryotes.

Chloroplasts

Similar to mitochondria, producing energy for the cell.
Utilize light energy instead of chemical energy.
Contain pigment chlorophyll in the thylakoid membrane that captures light.
Produce ATP by exciting electrons using an energy gradient.
Have their own genetic and protein material.

Vacuoles

Large fluid-filled sacs.
Help with structure and can contain water, sugar, salts, pigments, and toxic materials.
Animal cells can have vacuoles, but they are much smaller and less important.

The Cytoplasm and its Cytoskeleton

Actin Filaments
- 7 nm in diameter.
- Long and flexible.
- Can form a mesh.
- Aid movement by attaching to motor proteins.
Microtubules
- 7nm in diameter
- Long and flexible
- Can form a mesh
- Aid movement by attaching to motor proteins.

Epithelial Tissues

Sheets of cells.
Create boundaries, important for ion transport.
Specialized cells can secrete enzymes, milk, mucus, sweat, and gut epithelial cells.
Rapid division in skin.
Cilia in the gut.
Provide information to the central nervous system (CNS) for senses like taste and smell.

Connective Tissues

Provide structural support (like bone and cartilage).
Blood is connective tissue situated within liquid extracellular matrix (plasma).
Adipose tissue (fat) stores energy, protects organs, and provides a barrier to heat loss.

Muscle Tissues

Skeletal muscles are responsible for general movement.
Cardiac muscles are responsible for heartbeat and blood circulation.
Smooth muscle lines the inner walls of organs like the gut and bladder.

Neural Tissues

Neurons vary in shape, but all encode and decode information.
They act as intermediaries between stimuli and responses.
Glial cells provide support and protection to neurons.
Form a barrier between the blood and nervous system, preventing harmful substances from entering the neural system.

Homeostasis

A state of equilibrium where physical and biochemical processes can occur within a narrow range of variables.

Phospholipids

The main structural unit of the cell membrane.
Organized into a bilayer.
Have three main structural units.
Amphipathic (both hydrophobic and hydrophilic).

Cholesterol

A steroid.
Maintains membrane fluidity.
Amphipathic.
Prevents membrane crystallization.

Glycolipids/Proteins

Carbohydrate chains attached to lipids or proteins.
Glycolipids are carbohydrate chains attached to lipids.
Glycoproteins are carbohydrate chains attached to proteins.
Important for cell recognition.
Important for maintaining fluidtiy.

Integral Proteins

Various forms and can often determine the specific function of a cell.
Types:
- Channel Proteins
- Carrier Proteins
- Cell Recognition Proteins
- Receptor Proteins
- Enzymatic Proteins

Membrane Permeability

Semi-permeable or selectively permeable.
Allows some molecules to pass freely (small, non-charged molecules like CO2 or O2), while others require carrier proteins (larger or charged molecules).
Movement across the membrane depends on the concentration gradient.
Molecules can travel down or against the gradient.

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Description

Test your knowledge on the fundamentals of cell biology, including the structure and function of prokaryotes, organelles such as the ER and Golgi apparatus, and the important role of the plasma membrane. This quiz covers essential concepts related to DNA, ribosomes, and lysosomes.