Features
Features:

Product Tour >

Edraw AI >

Paid Plans:

Individuals >

Business >

Eduaction >
Resources
Blog

History

How-tos & Tips

Discovery

Biography

Business Analysis

Examples

AI concept Map

Free AI Mind Map Generator

Onenote Mind Map

Bcg Matrix Examples

Nike Marketing Strategy

Unilever SWOT Analysis

Make Mind Maps in Google Docs

Guide

FAQs

What's New

Resource Center
Templates
All Templates

Brain Storming Templates

Strategy and Planning Templates

Project Management Templates

Product Management Templates

Human Resources Templates

Agile Workflow Templates

Marketing Templates

Education Templates

Fun and Games Templates

User Gallery
Download
Pricing
Enterprise

MindMap Gallery Chapter 2 Basic Functions of Cells

Chapter 2 Basic Functions of Cells

Chapter 2: Basic functions of cells, including the basic functions of cell membranes, transmembrane signal transduction functions of cells, bioelectrical activities of cells, and contractile functions of muscle cells.

Edited at 2023-10-23 20:06:52

PlotWizard

Recent works View more works>>

Chapter 2 Basic Functions of Cells

PlotWizard

Recent works View more works>>

Recommended to you
Outline

Chapter 2 Basic Functions of Cells

Section 1 Basic functions of cell membrane

1. Material transport function of cell membrane

simple diffusion

Concept: The way fat-soluble small molecule substances are transported from the high concentration side to the low concentration side of the membrane.

Features: ① Fat-soluble small molecule ② Does not require protein participation ③ High concentration - low concentration (concentration difference) ④ Does not consume energy

Influencing factors: ①Permeability ②Concentration difference

facilitated diffusion

Concept: The way in which non-fat-soluble or very little fat-soluble substances are transported from the high-concentration side of the membrane to the low-concentration side with the help of membrane proteins.

Features: ① Non-fat-soluble or very little fat-soluble substances ② Requires the participation of protein ③ High concentration-low concentration ④ Does not consume energy

⒈Diffusion facilitated by carrier

Substances such as glucose and amino acids pass through the cell membrane in this way.

Features: ① Highly specific: a carrier can only choose one substance to bind ② Saturation phenomenon: the number is limited ③ Competitive inhibition: when the transport of one substance increases, the transport of another substance will decrease.

2. Facilitated diffusion through channels

Features: ① Ion selectivity: each channel is only open to the corresponding ion ② Gating property

active transport

Features: ① Small molecule substances or ions ② Cell membrane proteins help ③ Inverse concentration difference/potential difference (low concentration-high concentration) ④ Energy consumption

type

primary active transport

High sodium outside the membrane High potassium inside the membrane

Take out 3 (sodium) and go home with 2 (potassium)

The physiological significance of sodium pump activity: ① The high intracellular potassium ions caused by sodium and potassium activities are a necessary condition for many metabolic reactions in cells ② The concentration difference between potassium ions and sodium ions inside and outside the membrane caused by sodium pump activity ③ Cells formed by sodium pump activity The high external sodium ion potential energy reserve is the driving force for the secondary active transport of other substances. ④ The sodium pump activity can maintain the transport activity of the sodium pump.

secondary active transport

Divided into symport and reverse transport

Glucose reabsorption by renal tubular epithelial cells Glucose absorption by small intestinal epithelium from the intestinal lumen

Entering and exiting the cell

Enter the cell

Cell entry refers to the process of macromolecules or particulate matter entering the cell from outside the cell.

Entry into the cell is divided into phagocytosis and swallowing

Material that enters the cell is in a solid state and is called phagocytosis

Substances entering cells are in liquid form and are called phagocytosis

Exocytosis refers to the process of expelling macromolecular substances or particulate substances from the inside of the cell to the outside of the cell.

2. Receptor function of cell membrane

Special proteins present in the cell membrane or within the cell that can specifically bind to certain chemicals and cause specific physiological effects are called receptors.

Section 2 Transmembrane signal transduction function of cells

1. Signaling mediated by G protein-coupled receptors

G protein-coupled receptors are a type of protein found on cell membranes. Because these receptors must pass through G proteins to function, they are called G protein-coupled receptors.

2. Signaling mediated by ion channel receptors

chemically gated ion channels

3. Enzyme-linked receptor-mediated signaling

tyrosine kinase receptor mediated

Guanylyl cyclase-mediated

Section 3 Bioelectrical Activity of Cells

1. Resting potential

Resting potential refers to the potential difference that exists on both sides of the cell membrane in a quiet state (there is a potential difference between inside and outside the cell)

The state of positive charge outside the membrane and negative charge inside the membrane maintained in the quiet state is called polarization.

The process or state of increasing resting potential is called hyperpolarization

The process or state in which the resting potential is reduced is called depolarization

After depolarization to the zero point, if it further becomes positive, showing a state of negative charge on the outside of the membrane and positive charge on the inside, it is called reverse polarization.

The process of restoring the cell membrane to the resting potential after depolarization or reverse polarization is called repolarization.

production mechanism

①There is a concentration difference between external ions within the cell membrane

②The cell membrane is selective in its permeability to ions in the resting state

The resting potential is mainly the electro-chemical equilibrium potential formed by the outflow of potassium ions, also known as the potassium ion equilibrium potential.

2. Action potential

Concept: After cells are effectively stimulated, a rapid and scalable potential change occurs based on the resting potential.

Rapid depolarization from -70mV to 30mV, forming the rising branch of the action potential

Rapidly repolarizes to a level close to the resting potential, forming the descending branch of the action potential.

Features

① "All or nothing" phenomenon: The action potential reaches its maximum value. Even if the intensity of stimulation is increased, the amplitude of the action potential will not increase accordingly. (The action potential either does not occur, but once it does, it reaches its maximum amplitude)

②Pulse type: There is always a certain time interval between action potentials, and multiple continuous action potentials do not fuse.

③Non-attenuating conduction: the amplitude and waveform will not decrease due to the increase in conduction distance

Threshold potential: The critical membrane potential value that triggers an action potential.

Necessary condition: Depolarization of the resting potential to reach the threshold potential is the generation of action potential.

3. Local potential

Concept: A small depolarization that occurs locally in the membrane after stimulation. Also called local excitement.

Features: ① Attenuating conduction ② No “all or nothing” phenomenon ③ Can be summed

Section 4 Contractile function of muscle cells

1. Transmission of excitement at the neuromuscular junction

Under a light microscope, the structure appears plate-like

The contact point between somatic motor nerve fibers and skeletal muscles is called the neuromuscular junction

The neuromuscular junction is composed of three parts: the pre-joint membrane, the post-joint membrane and the joint space.

process

Acetylcholine binds to acetylcholine receptors, calcium channels open, and calcium ions flow in

Premembrane voltage-gated calcium channels open, allowing calcium ions to flow in

One nerve impulse only causes one muscle cell to excite, showing a one-to-one relationship.

Features

①One-way transmission: can only be transmitted from the front membrane to the rear membrane

②Time delay

③Susceptible to changes in the internal environment

2. Contraction mechanism of skeletal muscles

(1) Microstructure of skeletal muscles

Features: Contains a large number of myofibrils and a rich myotube system, and their arrangement is highly regular and orderly

Myofibrils and sarcomeres

The long axis of each myofibril presents regular alternating light and dark segments, called light and dark bands respectively.

The area between two adjacent Z lines is called a sarcomere, which is the most basic unit of muscle contraction and relaxation.

Molecular composition of myofilaments

Thick myofilaments are mainly composed of myosin

The head regularly protrudes from the surface of the thick muscle filaments on both sides of the M line, forming a cross bridge.

Thick myofilaments are mainly composed of actin, tropomyosin, and troponin.

myotubular system

Myotube system refers to the membranous cystic tube-like structure surrounding each myofibril.

Pipeline system

Tubes that run perpendicular to myofibrils are called transverse canals or T-tubes

Tubes that run parallel to myofibrils are called longitudinal tubes

Each transverse tube and the terminal pools on both sides form a triple tube

(ii) Contractile mechanism of skeletal muscles

⒈Myofilament sliding theory

⒉The sliding process of myofilaments

(iii) Excitation-contraction coupling of skeletal muscles

The intermediary process that links the action potential of muscle cells to mechanical contraction is called excitation-contraction coupling

Process: ① The action potential of the muscle cell is transmitted to the triple canal through the transverse canal system ② The release of calcium ions by the terminal cisternae ③ Calcium ions trigger the sliding of myofilaments ④ The recycling of calcium ions by the terminal cisternae

3. Contraction forms of skeletal muscles

(1) Isometric and isotonic contraction

Isometric contraction: Increase in tension without shortening in length

Isotonic contraction: only a shortening of length without a change in tension

(ii) Monoconstriction and tetanic contraction

Single contraction: When the muscle receives an effective stimulus, an action potential is triggered, resulting in a contraction and relaxation. This form of contraction is called a single contraction.

When a muscle is subjected to continuous effective stimulation, the fusion of muscle contractions that can be caused is called a tetanic contraction.

(iii) Main factors affecting skeletal muscle contraction

front load

active tension

passive tension

Optimum initial growth

afterload

Muscle contractility