Anatomy of the cell Flashcards
What is the basic unit of living things?
The cell
Performs all functions of life, including growth, metabolism, development, reproduction, carrying genetic material, and maintaining homeostasis.
What are the main functions performed by cells?
- Growth
- Metabolism
- Development
- Reproduction
- Carries genetic material
- Adaptation
- Respiration
- Homeostasis
These functions are essential for the survival and proliferation of living organisms.
When did the first organic molecules evolve?
About 3 billion years ago
This is believed to have occurred in the massive oceans of primitive Earth.
What distinguishes prokaryotic cells from eukaryotic cells?
Prokaryotes have no nucleus; eukaryotes have a distinct nucleus
Eukaryotic cells contain DNA combined with protein to form chromosomes.
Who first examined the structure of cork and named ‘cells’?
Robert Hooke
His work led to the discovery of the cell as the basic unit of life.
What did Mathias Schleiden and Theodor Schwann contribute to cell theory?
They developed the theory that all living organisms are composed of cells
This foundational concept in biology emphasizes the cellular nature of life.
What did Rudolf Virchow state about modern cells?
Modern cells can arise only from pre-existing cells
This expanded the cell theory to include the concept of cellular division.
What is the typical size limitation of cells?
Restricted to 10-30 μm in diameter
Smaller cells have a proportionately larger surface area, which allows for better control of cellular activity.
What is the cell membrane also known as?
Plasmalemma
It serves as a flexible, elastic barrier between the cytoplasm and the outside environment.
What are the primary components of the cell membrane?
- Proteins
- Phospholipids
- Cholesterol
- Lipids
- Carbohydrates
These components work together to maintain the structure and function of the membrane.
What is the structure of the cell membrane described as?
Fluid mosaic model
This model describes the cell membrane as a flexible layer made of lipid molecules with embedded proteins.
What types of materials pass easily through the cell membrane?
- Lipid-soluble materials
- Oxygen molecules
- Carbon dioxide molecules
Water-soluble molecules typically do not pass through easily.
What are integral proteins?
Proteins found within the lipid bilayer
They play crucial roles in various cellular functions.
What is the glycocalyx?
A ‘sugar coating’ covering the surface of cells
It consists of proteins and lipids attached to sugar groups and plays a role in cell adhesion.
What are caveolae?
Small 50-nanometer hollow spaces within the plasma membrane
They are produced from rafts in the plasma membrane that contain protein caveolin.
What are the functions of flagella?
Move cells through fluid and propel the cell forward by undulating
Flagella occur singly and are significantly longer than cilia.
What is the cytoplasm?
Inner substance of the cell excluding the nucleus
It appears as a nondescript bag of gel with various components.
What is the primary function of the cytoskeleton?
Provides support and shape to the cell
It also enables cell movement and anchors organelles.
What are the three types of fibers that comprise the cytoskeleton?
- Microfilaments
- Intermediate filaments
- Microtubules
Each type plays a unique role in maintaining cellular structure and function.
What is the function of the centrosome?
Building and breaking down microtubules
It is located near the nucleus and plays a critical role in cell division.
What are organelles?
‘Little organs’ within the cytoplasm that possess specialized cellular functions
Examples include mitochondria, ribosomes, and lysosomes.
What do mitochondria do?
Produce most of the energy to fuel the cell
They are the largest of the organelles and contain their own DNA.
What is the function of ribosomes?
Important site for protein synthesis
They consist of two globular subunits made of protein and ribosomal RNA.
What are the two types of endoplasmic reticulum?
- Rough ER
- Smooth ER
Rough ER has ribosomes on its surface and is involved in protein production; smooth ER synthesizes and stores lipids.
