Biology Chapter 3 Flashcards

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Questions and Answers

What is the plasma membrane of the cell composed of?

The plasma membrane is composed of two layers of phospholipids and cholesterol.

What are protein molecules?

Proteins on the membranes serve as receptors and help transport substances.

Where are cholesterol molecules found?

Cholesterol is found in the plasma membrane.

What are lysosomes?

Lysosomes are organelles that contain enzymes for digestion. Signup and view all the answers

What is the Golgi apparatus?

The Golgi apparatus is a structure that processes, packages, and delivers proteins and lipids. Signup and view all the answers

What are centrioles?

Centrioles are paired organelles that assist in cell division. Signup and view all the answers

What is a nucleolus?

The nucleolus is a dense region in the nucleus important for ribosome formation. Signup and view all the answers

What is cilia?

Cilia are hair-like extensions on the surface of cells. Signup and view all the answers

What does the nucleolus do?

The nucleolus makes ribosomes. Signup and view all the answers

What is flagellum?

A flagellum is a long projection that enables cell movement. Signup and view all the answers

What is phagocytosis?

Phagocytosis is the process of cell eating. Signup and view all the answers

What happens when a blood cell is placed in an isotonic solution?

The red blood cell remains unchanged. Signup and view all the answers

What is hypertonic?

A hypertonic solution has excessive concentration which causes cells to lose water. Signup and view all the answers

What is the difference between active and passive transport?

Active transport requires energy; passive transport does not. Signup and view all the answers

How does DNA differ from RNA?

RNA contains ribose, while DNA does not. Signup and view all the answers

What is the largest cell in the body?

The ovum is the largest cell in the body. Signup and view all the answers

Where is the cytoplasm and interstitial fluid found?

Cytoplasm is inside the cell; interstitial fluid bathes every cell. Signup and view all the answers

What makes up the cytoskeleton?

The cytoskeleton comprises microfilaments and microtubules. Signup and view all the answers

What are microvilli?

Microvilli are small projections that increase the cell's surface area. Signup and view all the answers

What happens during transcription?

During transcription, DNA unwinds and messenger RNA is formed. Signup and view all the answers

What is the function of transfer RNA?

tRNA translates mRNA codons into amino acids. Signup and view all the answers

Study Notes

Plasma Membrane

Composed of a bilayer of phospholipids, providing a fluid framework.
Cholesterol molecules stabilize the membrane to prevent breakage.

Protein Molecules

Function as transporter channels and carriers for selective substance movement through the plasma membrane.
Some proteins serve as receptors for other molecules.

Lysosomes

Membranous organelles that contain enzymes for hydrolysis.
Digest nutrients and destroy invading microbes, acting as protective "digestive bags."

Golgi Apparatus

Consists of flattened stacks that process, package, and deliver proteins and lipids from the endoplasmic reticulum (ER).
Vesicles transport newly formed proteins for further processing and packaging.

Centrioles

Paired organelles found in the centrosome, essential for cell division.
Composed of microtubules, aiding in the formation of spindle fibers.

Nucleus and Nucleolus

The nucleus houses most genetic information and controls cellular activities, including reproduction.
The nucleolus is a dense region critical for ribosome formation.

Cilia and Flagella

Cilia are fine, hair-like extensions that help cells sense their environment and can move.
Flagella are longer projections that propel cells; the only human example is found in sperm.

Active and Passive Transport

Active transport requires energy (ATP) for substance movement against concentration gradients; passive transport does not.
Processes include diffusion, osmosis, filtration, and dialysis.

Mitosis Stages (IPMAT)

Interphase: DNA replication, cell growth.
Prophase: Chromatin condenses, spindle fibers form.
Metaphase: Chromosomes align at the cell's center.
Anaphase: Chromosomes are pulled away from the center.
Telophase: Nuclear envelope forms, cytoplasm divides.

Cell Membrane Functions

Separates cell contents from interstitial fluid, maintaining internal environment.

Ribosomes

Composed of ribosomal RNA (rRNA) and proteins, essential for protein synthesis.

Endoplasmic Reticulum (ER)

A network of membranes; Rough ER synthesizes proteins, while Smooth ER produces membranes and other substances.

Mitochondria

Composed of two membranes, involved in energy production through cellular respiration, creating ATP.

Differences Between DNA and RNA

DNA lacks ribose and is double-stranded; RNA contains ribose and uracil instead of thymine.

Cytoplasm vs. Interstitial Fluid

Cytoplasm is the fluid within the cell; interstitial fluid surrounds cells, providing nutritional support.

Cytoskeleton Composition

Composed of microfilaments and microtubules that provide structural support and facilitate movement.

Microvilli

Small projections that increase surface area for absorption.

Transcription and Translation

Transcription: DNA unwinds and mRNA is synthesized as a copy of the gene.
Translation: Ribosomes read mRNA codons to synthesize proteins via tRNA.

Functions of Transfer RNA (tRNA)

Acts as an adapter during protein synthesis by bringing specific amino acids to the mRNA.

Organelles Containing Nucleic Acids

Nucleus (DNA), Ribosomes (rRNA), Mitochondria (circular DNA), Chloroplasts (similar to mitochondria).

Isotonic Solutions

Solutions with equal concentration of solutes as inside cells, causing no net water movement and maintaining cell shape.

Hypertonic Solutions

Solutions with higher concentrations, causing cells to lose water and shrink (crenation).

Largest and Smallest Human Cells

The ovum is the largest at 150 micrometers; red blood cells are the smallest at 7.5 micrometers.

Ion Pumps

Specialized proteins that actively transport ions across membranes using ATP, specific to particular ions like sodium and potassium.

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Description

Test your knowledge on the components of the plasma membrane in cells with these flashcards. This quiz covers the structure and function of phospholipids and cholesterol in maintaining cellular integrity. Ideal for students studying biology at an introductory level.