General definition of cell, cell structure, the difference between prokaryotic and eukaryotic cell

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The cell, the fundamental unit of all living beings, is a complex structure composed of different elements working in harmony.
The plasma membrane: the protective envelope
The plasma membrane is a semi-permeable barrier that delimits the cell and separates it from its environment. It consists of a double layer of phospholipids, in which various proteins are integrated. These proteins play a crucial role in the transport of substances across the membrane, cell communication and cell recognition.
The cytoplasm: the internal environment
The cytoplasm is the aqueous medium inside the cell. It contains many organelles, inclusions, and the cytosol. The cytosol is the liquid part of the cytoplasm, rich in enzymes and molecules necessary for the chemical reactions of the cell.
The Core: The Control Center
The nucleus is a characteristic organelle of eukaryotic cells. It contains the genetic information of the cell in the form of DNA, organized into chromosomes. The nucleus is surrounded by a nuclear envelope pierced by nuclear pores that allow the exchange of molecules between the nucleus and the cytoplasm.
Organelles: specialized factories
Organelles are specialized structures present in the cytoplasm. Each of them fulfills a specific function:
Mitochondria: Nicknamed the "power plants" of the cell, they are the seat of cellular respiration, a process that produces the energy needed by the cell.
The endoplasmic reticulum: A network of membranes involved in the synthesis of proteins and lipids.
The Golgi apparatus: A set of flattened sacs that modify, package, and distribute proteins and lipids synthesized by the endoplasmic reticulum.
Lysosomes: Small vesicles containing digestive enzymes that break down unnecessary or damaged molecules.
The cytoskeleton: the skeleton of the cell
The cytoskeleton is a network of protein filaments that gives the cell its shape, allows it to move, and organizes its organelles. It is made up of three types of filaments: microfilaments, intermediate filaments, and microtubules.
The differences between prokaryotic and eukaryotic cells
There are two main types of cells: prokaryotic cells (bacteria) and eukaryotic cells (animals, plants, fungi). Prokaryotic cells are simpler and do not have a nucleus or membrane-bound organelles. Eukaryotic cells, on the other hand, are more complex and have a nucleus and many organelles.

Extra information

the notebook, pen

Location

Online from Algeria

Age

Children (7-12 years old)

Teenagers (13-17 years old)

Adults (18-64 years old)

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Beginner

Intermediate

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Duration

90 minutes

The class is taught in

French

Arabic

English

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Biology

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(GMT -05:00)

New York

Online via webcam

Mon

Tue

Wed

Thu

Fri

Sat

Sun

00-04

04-08

08-12

12-16

16-20

20-24

plasma membrane: structure, function, properties

16 € /h

Structure of the plasma membrane
The plasma membrane is mainly composed of:

Phospholipids: These amphipathic molecules (having both a hydrophilic and a hydrophobic part) are organized into a double lipid layer. This structure gives the membrane its semi-permeable barrier property.
Proteins: They are integrated into the lipid bilayer and perform various functions: transport of molecules, reception of signals, cellular recognition, etc.
Carbohydrates: Linked to lipids (glycolipids) or proteins (glycoproteins), they play an important role in cell recognition and cellular interactions.
Function of the plasma membrane
Selective barrier: The plasma membrane allows the selective passage of certain molecules while preventing others.
Transport: Membrane proteins provide passive (simple or facilitated diffusion) or active (pumps) transport of molecules across the membrane.
Receiving signals: Membrane receptors allow the cell to detect and respond to signals from its environment.
Cell recognition: Molecules present on the surface of the membrane allow cells to recognize and interact with each other.
Maintenance of homeostasis: The plasma membrane helps maintain a stable intracellular environment by regulating exchanges between the cell and its environment.
Properties of the plasma membrane
Fluidity: The plasma membrane is not a rigid structure but rather fluid, which allows it to deform and change shape.
Asymmetry: The two faces of the plasma membrane have different compositions, which gives the membrane polarity.
Plasma membrane models
Fluid mosaic model: This model, the most accepted, describes the membrane as a constantly changing mosaic of lipids and proteins.

Marie

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With a bachelor's and master's degree in speech therapy (both with honors), I offer individualized instruction tailored to each student's needs. I provide homework help and exam preparation support. Revision sheets and self-assessment tests will be developed and offered regularly. My goal is to help students progress without overwhelming them. I assign homework after each lesson and provide weekly progress reports. The program will be developed in consultation with the student, based on their abilities and individual requirements.

Narayan

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Biology lessons taught by an engineering graduate with over 16 years of experience, as of 2024, in teaching mathematics (up to undergraduate level), biology (up to secondary level, including IGCSE, GCSE, and S5), and physics and chemistry (upper secondary levels, IB, and A level).

With extensive experience in tutoring Biology, I provide specialized lessons for students up to the GCSE, IGCSE, and European S5 levels. I aim to make Biology engaging and accessible, helping students not only understand the material but also excel in their exams and coursework. Whether you're studying ecosystems, human physiology, genetics, or cell biology, I tailor my lessons to meet your individual learning needs.

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For mathematics, I provide lessons for students up to the bachelor's level, including bachelor students, IB (Math SL and Math HL) students, AS/A-level students, European S6 and S7 level students, GCSE students, and IGCSE students.

Science (physics and chemistry) courses are available for students up to the European upper secondary level, including IB and A level.

Science (biology) lessons are available for students up to the European secondary level, GCSE level, and IGCSE level.

Currently, I am teaching:
1. GCSE students
2. IGCSE students
3. IB students
4. European School students
5. AS/A level students

My current students are from the following schools:
1. St Georges International School, Luxembourg, Edexcel (Pearson) Curriculum (10 students)
2. International School of Luxembourg, Luxembourg, IB Curriculum (6 Students)
3. Lycée Athénée de Luxembourg, Luxembourg, IB Curriculum (4 Students)
4. Lycée - International School Michel Lucius, Luxembourg, Cambridge Curriculum (4 Students)
5. European School Kirchberg, Luxembourg, European Curriculum (4 students)
6. Lycée Aline Mayrisch, Luxembourg, Luxembourgish curriculum (1 student)
7. International School of the Hague, Netherlands, IB Curriculum (1 student)
8. International School Of Nice, France, IB Curriculum (2 students)
9. Merchiston Castle School, Edinburgh, Scotland, Edexcel (Pearson)/Cambridge (1 students)
10. Silverline Private School, Limassol, Cyprus, UK national Curriculum (1 Student)
11. North Broward Preparatory School, Florida, USA, IB Curriculum (1 Student)
12. King Solomon International School, Israel, IB Curriculum (1 student)

In addition to helping students with their coursework, I also focus on developing effective study habits and test-taking strategies to ensure that they are fully prepared for their exams. My goal is to help each student achieve their best possible results.

If you’re a GCSE, IGCSE, or European S5 student looking for expert Biology tutoring, I’m here to help you succeed. Contact me today to begin your journey toward academic excellence in Biology!

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If you're looking for an organised and professional teacher to help you achieve your academic goals, look no further! The IB science subjects can be extremely difficult to go through on your own, and I'll be glad to use my experience to help you out.

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- Initial test or interview to assess your level.
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Alexandros

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I can offer help in courses of Chemistry and Biology. This applies to all levels from High School, A-levels, IB up to university courses. I am a graduate of the Maastricht Science Programme from the University of Maastricht.
I believe that subjects such as biology or chemistry should be understood and not just memorized and I have worked hard as a tutor in MSP to convey this message to my students as well. I am excited for this new endeavor and I am eager to help you achieve your goals.

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Shaymaa

4.8

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science is an exciting subject that helps us understand the world around us. In this class, you’ll learn about the fundamental principles of science and how they apply to everyday life. You’ll explore topics such as earth and life sciences, biology, and physics, and learn how to apply these concepts to solve real-world problems.

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Ilana

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I received my International Baccalaureate diploma with Biology as one of my higher-level subjects in May 2023. I consistently got 6's and 7's in my biology exams, including the final exam. I am willing to offer support with IB style questions (structured and multiple choice) as well as tutor areas of the subject that are challenging and look over IA's. I believe that I am equipped to tutor both higher-level and standard-level IB students as well as MYP students studying biology. I have been tutoring online since September 2023 and have recieved great feedback from clients!

Abrar

4.8

(10)

Expert Online/in-person Chemistry/Biology Tutor | MSc in Biochemistry | 6+ Years of International Teaching Experience | Specializing in IGCSE, GCSE, A-Level, IB, and University level.

I am a qualified, experienced, and certified international tutor with a strong familiarity with the Cambridge IGCSE/A-Levels/O-Levels & IB Diploma curricula. I offer both ONLINE and IN-PERSON lessons in CHEMISTRY, and BIOLOGY, following the British, American, and Indian curricula.
My classes are available at affordable rates and can be conducted in-person or online. I adopt a student-oriented teaching style, striving to provide the best private lessons for my students.

With 6 years of professional experience in science (Chemistry, and biology), I am well-versed in both the British and American curricula and I possess a high level of competency. I have taught students from various countries, including Belgium, Spain, Switzerland, Japan, the USA, the Caribbean, the UK, India, China, Singapore, Malaysia, Turkey, the Netherlands, Luxembourg, Germany, France, Italy, and South Africa.

Book a lesson with me, and we can start at the time that suits you.
Extra information
•Currently, I am teaching:
1. GCSE students
2. IGCSE students
3. IB students
4. European School students
5. AS/A level students
6. American curriculum

•Boost your understanding: Clear explanations, engaging activities, and practice exercises to solidify your knowledge.
Master exam prep: Conquer past papers, tackle tricky concepts, and build confidence for upcoming tests.
Individualized approach: Personalized curriculum and learning pace to fit your needs and goals.

•Flexible scheduling: Online or in-person lessons to suit your busy schedule.

I also provide homework help for school students. The progress of students can be assessed through periodic tests conducted as per the requirements of parents or the students themselves."

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Robert

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As a Franco-Belgian teacher, I offer private lessons in physics, chemistry and biology for secondary and higher levels. I specialize in secondary level up to 5th year Belgian.

I travel, if necessary, to your home in the Brussels region as well as in Walloon and Flemish Brabant, with a minimum course duration of 2 hours. With extensive experience, I offer numerous exercises to consolidate knowledge. Distance learning is also possible via platforms such as Skype, Facebook, etc. For students in France, lessons are done exclusively remotely.

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Hagar

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5 years of experience in teaching chemistry and biology to school and university students. She holds a Bachelor of Pharmacy in Pharmaceutical Sciences in addition to a Master’s degree in Analytical Chemistry with honors.
The student will learn to understand chemical equations, compounds, and reactions, and enjoy studying and applying the lessons with ease and simplicity through a simplified explanation and simple-to-understand means of clarification.

Olatade

4.8

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Join my fun and engaging KS3 and A level tutoring sessions where we dive into the exciting worlds of Chemistry and Biology! Our sessions will be designed to make learning enjoyable and interactive, helping students build confidence and mastery in each subject. In Chemistry, we tackle real-world situations involving physical and organic chemistry, make use of puzzles that sharpen critical thinking skills of reactions and watch exciting videos of reactions. And in Biology, we explore the wonders of life, from ecosystems to human anatomy, making science come alive! Get ready for a learning adventure that’s both educational and enjoyable!

Fatima

4.8

(10)

Biology Courses – All Levels

With a Master's degree in Microbiology and Virology and solid experience in biotechnology and scientific research, I offer courses adapted to each level and objective, from college to university.

Biology Courses – All Levels
Do you want to understand biology clearly and effectively? I offer courses adapted to all levels, from middle school to university.
✨ What I offer:
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Dr.Ibrahim

4.8

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This course offers an integrated introduction to the core areas of science, including biology, physics, earth science, and environmental science. Students will explore scientific concepts, principles, and methods through hands-on experiments, observations, and problem-solving activities. Emphasis is placed on developing scientific literacy, critical thinking, and an understanding of the scientific method. The course encourages curiosity about the natural world and prepares students to apply scientific knowledge to everyday life and future academic study.

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4.8

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I am a 2021 IGCSE graduate and a 2023 IB graduate, now studying Veterinary Medicine at the University of Edinburgh. Having recently completed these programmes myself, I understand the challenges students face and how to overcome them effectively.

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- IB & IGCSE syllabus coverage across core and extended levels
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I offer private tutoring at home for all levels, from primary school to high school. A typical session consists of the following steps:

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Michiel

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Need help with maths or biology?
As a biomedical scientist with a PhD in Medicine and Health Sciences, I enjoy helping students of all ages to better understand the material and learn with greater confidence. We work at your own pace and in a way that suits your learning style.

How does a lesson work?
In the first session, we identify the main difficulties together. From there, we build up step by step. I encourage questions and provide practical tips and strategies to make studying more effective.

We work through exercises together, discuss examples, and then move on to more challenging problems to deepen understanding. This approach ensures you’re well prepared for your tests and exams.

A positive learning experience
Learning should be enjoyable. With a patient, motivating and clear approach, I create a relaxed environment where it’s okay to make mistakes, and no question is too much to ask — because that’s how real learning happens.

Interested?
Feel free to get in touch for more information or to arrange your first lesson. I’ll be happy to help you move forward!