Anatomy & Physiology: Cell Structure, Membrane Transport, Cell Cycle, and Protein Synthesis Study Guide

Study Guide - Smart Notes

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Q1. What does the cell theory state?

Background

Topic: Cell Theory

This question tests your understanding of the foundational principles that define what a cell is and its role in living organisms.

Key Terms:

Cell Theory
Organism

Step-by-Step Guidance

Recall the three main tenets of cell theory. Think about what the theory says about the structure and function of cells in living things.
Consider how the theory addresses the origin of new cells.
Reflect on how the theory applies to both unicellular and multicellular organisms.

Try solving on your own before revealing the answer!

Final Answer:

The cell theory states:

All living things are composed of one or more cells.
The cell is the basic unit of structure and function in living organisms.
All cells arise from pre-existing cells.

This theory is fundamental to understanding biology and the continuity of life.

Q2. What are the 3 main parts of the cell?

Background

Topic: Cell Structure

This question is about identifying the major structural components of a typical eukaryotic cell.

Key Terms:

Plasma membrane
Cytoplasm
Nucleus

Step-by-Step Guidance

Think about the outer boundary of the cell and what it is called.
Consider the material inside the cell but outside the nucleus—what is this region called?
Identify the structure that contains the cell's genetic material.

Try solving on your own before revealing the answer!

Final Answer:

Plasma (cell) membrane
Cytoplasm (which includes cytosol and organelles)
Nucleus

These are the three main structural components of a typical eukaryotic cell.

Q3. What is meant by the fluid mosaic model?

Background

Topic: Cell Membrane Structure

This question tests your understanding of how the plasma membrane is organized and functions.

Key Terms:

Phospholipid bilayer
Proteins
Fluid mosaic model

Step-by-Step Guidance

Recall what the "fluid" part of the model refers to in terms of membrane movement.
Think about what the "mosaic" part describes regarding the components of the membrane.
Consider how proteins and lipids are arranged and how they move within the membrane.

Try solving on your own before revealing the answer!

Final Answer:

The fluid mosaic model describes the plasma membrane as a flexible, dynamic structure made of a phospholipid bilayer with proteins and other molecules embedded in it. The "fluid" part means that lipids and proteins can move laterally within the layer, while "mosaic" refers to the patchwork of proteins that float in or on the fluid lipid bilayer.

Q4. How does the arrangement of hydrophilic and hydrophobic regions create a semipermeable membrane that regulates contents flowing into and out of the cell?

Background

Topic: Membrane Permeability

This question is about how the structure of the phospholipid bilayer allows selective movement of substances.

Key Terms:

Hydrophilic (water-loving) heads
Hydrophobic (water-fearing) tails
Semipermeable membrane

Step-by-Step Guidance

Recall the structure of a phospholipid and how they arrange themselves in the membrane.
Think about which parts of the membrane interact with water and which do not.
Consider how this arrangement affects the movement of different types of molecules (polar vs. nonpolar) across the membrane.

Try solving on your own before revealing the answer!

Final Answer:

The hydrophilic heads of phospholipids face outward toward the water inside and outside the cell, while the hydrophobic tails face inward, away from water. This arrangement forms a semipermeable barrier that allows some substances (like small nonpolar molecules) to pass through easily, while blocking others (like large or charged molecules), thus regulating what enters and exits the cell.

Q5. What are the main types of cell junctions? How do they function?

Background

Topic: Cell Junctions

This question tests your knowledge of how cells connect and communicate with each other.

Key Terms:

Tight junctions
Desmosomes
Gap junctions

Step-by-Step Guidance

List the three main types of cell junctions found in animal tissues.
For each type, think about its primary function (e.g., sealing, anchoring, communication).
Consider examples of where each type might be found in the body.

Try solving on your own before revealing the answer!

Final Answer:

Tight junctions: Seal cells together to prevent leakage of molecules between them (e.g., in the intestines).
Desmosomes: Anchor cells together, providing mechanical strength (e.g., in skin and heart tissue).
Gap junctions: Allow direct communication between cells by permitting ions and small molecules to pass (e.g., in cardiac muscle).

Q6. What is cytosol? What is an organelle?

Background

Topic: Cell Components

This question is about distinguishing between the fluid part of the cytoplasm and the specialized structures within the cell.

Key Terms:

Cytosol
Organelle

Step-by-Step Guidance

Define cytosol and consider what it contains.
Define organelle and think about examples of organelles in the cell.
Differentiate between the two in terms of structure and function.

Try solving on your own before revealing the answer!

Final Answer:

Cytosol is the fluid portion of the cytoplasm, where many metabolic reactions occur. An organelle is a specialized structure within the cell that performs a specific function, such as the mitochondrion, endoplasmic reticulum, or Golgi apparatus.

Q7. What are the two basic methods of membrane transport? What are the passive processes? What are the active processes? What is an aquaporin?

Background

Topic: Membrane Transport

This question tests your understanding of how substances move across the cell membrane, both with and without energy input.

Key Terms and Concepts:

Passive transport
Active transport
Aquaporin

Step-by-Step Guidance

Identify the two main categories of membrane transport based on energy usage.
List the types of passive transport (e.g., diffusion, facilitated diffusion, osmosis).
List the types of active transport (e.g., primary active transport, secondary active transport, endocytosis, exocytosis).
Define what an aquaporin is and its role in membrane transport.

Try solving on your own before revealing the answer!

Final Answer:

Two basic methods: Passive transport (no energy required) and active transport (requires energy, usually ATP).
Passive processes: Simple diffusion, facilitated diffusion, osmosis.
Active processes: Primary active transport (e.g., sodium-potassium pump), secondary active transport, endocytosis, exocytosis.
Aquaporin: A membrane protein that forms channels specifically for water to pass through the membrane more efficiently.

Q8. What is osmosis? Isotonic? Hypotonic? Hypertonic?

Background

Topic: Osmosis and Tonicity

This question is about the movement of water across membranes and the effects of different solute concentrations.

Key Terms:

Osmosis
Isotonic
Hypotonic
Hypertonic

Step-by-Step Guidance

Define osmosis in terms of water movement and concentration gradients.
Explain what happens to a cell in an isotonic solution.
Describe the effects of a hypotonic solution on a cell.
Describe the effects of a hypertonic solution on a cell.

Try solving on your own before revealing the answer!

Final Answer:

Osmosis: The diffusion of water across a semipermeable membrane from an area of lower solute concentration to higher solute concentration.
Isotonic: Solution with equal solute concentration as the cell; no net water movement.
Hypotonic: Solution with lower solute concentration than the cell; water enters the cell, which may swell or burst.
Hypertonic: Solution with higher solute concentration than the cell; water leaves the cell, causing it to shrink.

Q9. What is facilitated diffusion as a passive method of membrane transport?

Background

Topic: Facilitated Diffusion

This question is about how certain molecules cross the cell membrane with the help of proteins, without energy input.

Key Terms:

Facilitated diffusion
Carrier proteins
Channel proteins

Step-by-Step Guidance

Recall what makes facilitated diffusion different from simple diffusion.
Think about the types of molecules that require facilitated diffusion.
Consider the role of membrane proteins in this process.

Try solving on your own before revealing the answer!

Final Answer:

Facilitated diffusion is a passive transport process where specific molecules move across the cell membrane through protein channels or carriers, down their concentration gradient, without the use of cellular energy (ATP).

Q10. What is the sodium-potassium (Na–K) pump as a method of active transport? How does it work? Be able to match/put in order or label the picture of the three steps of this process!

Background

Topic: Active Transport Mechanisms

This question is about the sodium-potassium pump, a key example of primary active transport in cells.

Key Terms and Formula:

Sodium-potassium pump (Na+/K+ ATPase)
ATP (adenosine triphosphate)
Concentration gradient

Step-by-Step Guidance

Recall that the pump moves sodium and potassium ions against their concentration gradients using ATP.
Identify the number of sodium ions pumped out and potassium ions pumped in per cycle.
Think about the sequence of steps: binding of ions, ATP hydrolysis, conformational change, and release of ions.
Consider how this process helps maintain the electrochemical gradient across the membrane.

Try solving on your own before revealing the answer!

Final Answer:

The sodium-potassium pump uses ATP to move 3 Na+ ions out of the cell and 2 K+ ions into the cell against their concentration gradients. The steps are:

3 Na+ ions bind to the pump inside the cell.
ATP is hydrolyzed, causing the pump to change shape and release Na+ outside.
2 K+ ions bind from outside, the pump returns to its original shape, and K+ is released inside the cell.

This maintains the resting membrane potential and is essential for nerve and muscle function.

Q11. As a form of active transport, what is exocytosis and endocytosis?

Background

Topic: Bulk Transport

This question is about how cells move large particles or volumes of substances across the membrane using vesicles.

Key Terms:

Exocytosis
Endocytosis
Vesicle

Step-by-Step Guidance

Define exocytosis and describe what happens to the vesicle and its contents.
Define endocytosis and describe the process of bringing substances into the cell.
Think about examples of each process in the body.

Try solving on your own before revealing the answer!

Final Answer:

Exocytosis is the process by which cells expel materials in vesicles that fuse with the plasma membrane. Endocytosis is the process by which cells take in materials by engulfing them in vesicles formed from the plasma membrane. Both require energy and are forms of active transport.

Q12. What is the cell cycle? What are the major phases?

Background

Topic: Cell Cycle

This question is about the sequence of events that a cell goes through from one division to the next.

Key Terms:

Cell cycle
Interphase
Mitotic (M) phase

Step-by-Step Guidance

Define the cell cycle and its purpose.
List the two major phases of the cell cycle.
Break down the subphases of interphase and the mitotic phase.

Try solving on your own before revealing the answer!

Final Answer:

The cell cycle is the series of events that cells go through as they grow and divide. The major phases are interphase (G1, S, G2) and the mitotic (M) phase, which includes mitosis and cytokinesis.

Q13. What are the phases of mitosis? What occurs in each phase of mitosis?

Background

Topic: Mitosis

This question is about the process of nuclear division and the events that occur in each stage.

Key Terms:

Prophase
Metaphase
Anaphase
Telophase

Step-by-Step Guidance

List the four main phases of mitosis in order.
For each phase, recall the key events (e.g., chromosome condensation, alignment, separation, reformation of nuclei).
Think about how you would identify each phase in a diagram or description.

Try solving on your own before revealing the answer!

Final Answer:

Prophase: Chromosomes condense, spindle forms, nuclear envelope breaks down.
Metaphase: Chromosomes align at the cell's equator.
Anaphase: Sister chromatids separate and move to opposite poles.
Telophase: Nuclear envelopes reform, chromosomes decondense.

Q14. What are the three stages of interphase? When does DNA replication occur?

Background

Topic: Interphase and DNA Replication

This question is about the preparation steps a cell takes before division, including when DNA is copied.

Key Terms:

G1 phase
S phase
G2 phase
DNA replication

Step-by-Step Guidance

List the three stages of interphase in order.
Recall what happens in each stage (growth, DNA synthesis, preparation for mitosis).
Identify during which stage DNA replication occurs.

Try solving on your own before revealing the answer!

Final Answer:

G1 phase: Cell grows and carries out normal functions.
S phase: DNA replication occurs.
G2 phase: Cell prepares for mitosis.

Q15. What does semiconservative mean in regard to DNA replication? Be able to take an example template strand and make a new DNA strand with correct complementary base pairs. (e.g., a TACTGC sequence on a template strand generates a new strand with the order ATGACG)

Background

Topic: DNA Replication

This question is about the mechanism of DNA replication and how base pairing works.

Key Terms:

Semiconservative replication
Complementary base pairing
Template strand

Step-by-Step Guidance

Define semiconservative replication and what it means for the new DNA molecules.
Recall the base pairing rules: A pairs with T, C pairs with G.
Given a template strand, write out the complementary sequence using the base pairing rules.

Try solving on your own before revealing the answer!

Final Answer:

Semiconservative replication means each new DNA molecule consists of one original (parental) strand and one newly synthesized strand. For a template strand TACTGC, the complementary strand would be ATGACG.

Q16. What is cytokinesis? When does it usually start? How is it recognized as happening during this phase of cell division?

Background

Topic: Cytokinesis

This question is about the division of the cytoplasm and how it is distinguished from mitosis.

Key Terms:

Cytokinesis
Cleavage furrow
Cell division

Step-by-Step Guidance

Define cytokinesis and how it differs from mitosis.
Recall when cytokinesis typically begins in relation to mitosis.
Describe the physical changes in the cell that indicate cytokinesis is occurring.

Try solving on your own before revealing the answer!

Final Answer:

Cytokinesis is the division of the cytoplasm to form two separate daughter cells. It usually starts during late anaphase or telophase and is recognized by the formation of a cleavage furrow that pinches the cell in two.

Q17. For the lab practical – be able to label the phases of mitosis from a picture of cells undergoing mitosis

Background

Topic: Identifying Mitosis Phases

This question is about visually recognizing the stages of mitosis in cell images.

Key Terms:

Prophase
Metaphase
Anaphase
Telophase

Step-by-Step Guidance

Review the visual characteristics of each mitosis phase (e.g., chromosome arrangement, spindle formation).
Practice matching images or diagrams to the correct phase based on these features.
Pay attention to the position and appearance of chromosomes and the nuclear envelope.

Try solving on your own before revealing the answer!

Final Answer:

Each phase of mitosis has distinct visual cues: prophase (condensed chromosomes, no nuclear envelope), metaphase (chromosomes aligned at the center), anaphase (chromatids pulled apart), telophase (chromosomes at poles, nuclear envelope reforms).

Q18. For protein synthesis, what serves as the blueprint?

Background

Topic: Protein Synthesis

This question is about the molecule that contains the instructions for building proteins.

Key Terms:

DNA
Gene

Step-by-Step Guidance

Recall where the genetic information for protein synthesis is stored in the cell.
Think about the role of genes in coding for proteins.

Try solving on your own before revealing the answer!

Final Answer:

DNA serves as the blueprint for protein synthesis, with genes providing the specific instructions for building each protein.

Q19. What is a gene? What is a triplet code?

Background

Topic: Genetic Code

This question is about the basic units of heredity and how genetic information is encoded.

Key Terms:

Gene
Triplet code (codon)

Step-by-Step Guidance

Define what a gene is in terms of DNA sequence and function.
Explain what is meant by the triplet code and how it relates to amino acids.

Try solving on your own before revealing the answer!

Final Answer:

A gene is a segment of DNA that contains the instructions for making a specific protein. The triplet code refers to the three-nucleotide sequences (codons) in DNA or mRNA that specify particular amino acids.

Q20. What is a ribosome, and what role does it have in protein synthesis?

Background

Topic: Ribosomes and Protein Synthesis

This question is about the cellular machinery responsible for assembling proteins.

Key Terms:

Ribosome
Translation

Step-by-Step Guidance

Define what a ribosome is and where it is found in the cell.
Describe the ribosome's function in the process of protein synthesis.

Try solving on your own before revealing the answer!

Final Answer:

A ribosome is a cellular organelle made of rRNA and proteins that serves as the site of protein synthesis (translation), where mRNA is decoded to build a polypeptide chain.

Q21. What are the three types of RNA that play a role in protein synthesis? How do they assist with protein synthesis?

Background

Topic: Types of RNA

This question is about the different RNA molecules involved in making proteins and their specific roles.

Key Terms:

mRNA (messenger RNA)
tRNA (transfer RNA)
rRNA (ribosomal RNA)

Step-by-Step Guidance

List the three main types of RNA involved in protein synthesis.
Describe the function of each type in the process of translation.

Try solving on your own before revealing the answer!

Final Answer:

mRNA: Carries the genetic code from DNA to the ribosome.
tRNA: Brings the correct amino acids to the ribosome during translation.
rRNA: Forms the core of the ribosome and catalyzes peptide bond formation.

Q22. What are the two phases of protein synthesis, and where do they occur?

Background

Topic: Protein Synthesis Phases

This question is about the two main steps in making a protein and their cellular locations.

Key Terms:

Transcription
Translation

Step-by-Step Guidance

Name the two phases of protein synthesis.
Identify where each phase takes place in the cell (nucleus or cytoplasm).

Try solving on your own before revealing the answer!

Final Answer:

The two phases are transcription (in the nucleus) and translation (in the cytoplasm at the ribosome).

Q23. Be able to take a template DNA strand and code it into RNA. (e.g., DNA sequence is AAT-CGT-TCG, then the mRNA corresponding codons are UUA-GCA-AGC)

Background

Topic: Transcription and Base Pairing

This question is about converting a DNA sequence into its corresponding mRNA sequence using base pairing rules.

Key Terms:

Transcription
mRNA
Base pairing rules (A-U, T-A, C-G, G-C)

Step-by-Step Guidance

Recall the base pairing rules for transcription: A pairs with U, T with A, C with G, G with C.
Given a DNA template strand, write out the complementary mRNA sequence using these rules.
Group the mRNA sequence into codons (sets of three nucleotides).

Try solving on your own before revealing the answer!

Final Answer:

For a DNA sequence AAT-CGT-TCG, the mRNA codons would be UUA-GCA-AGC, following the base pairing rules during transcription.

Q24. What occurs during translation? Transcription?

Background

Topic: Protein Synthesis Steps

This question is about the two main processes in protein synthesis and what happens in each.

Key Terms:

Transcription
Translation

Step-by-Step Guidance

Define what happens during transcription (DNA to mRNA).
Define what happens during translation (mRNA to protein).
Identify the cellular locations where each process occurs.

Try solving on your own before revealing the answer!

Final Answer:

During transcription, a segment of DNA is used as a template to make mRNA in the nucleus. During translation, the mRNA is read by ribosomes in the cytoplasm to assemble a protein from amino acids.