1.1 Introduction to Cells Flashcards
What is the cell theory? (3)
- All living things are made of cells
- Cells are the smallest unit of life
- All cells only come from pre-existing cells
What does every cell have? (3)
- A membrane
- to separate contents from the outside
- Genetic material, i.e. DNA/RNA
- An energy release system
- to power the whole cell
What three examples test the cell theory? (3, SPELLING)
- Striated muscle
- Aseptate hyphae
- Giant Algae
Describe the striated muscle. (2)
How does it challenge the cell theory? (2)
- type of tissue (muscle fibre) where the fibres are similar to cells
- cells are surrounded a plasma membrane, those within the membrane fuse together
- causes fibres to become very long (~30mm)
- contain many nuclei within a single membrane
- challenges idea that cells always function as individuals
Describe the aseptate hyphae. (2)
How does it challenge the cell theory? (2)
- fungi may have hyphae (thread-like structures)
- hyphae are separated into cells by septa (internal walls)
- some fungi don’t have septa
- continuous cytoplasm along the entire hyphae
- long structure similar to a cell
- many nuclei present
- challenges idea that living structures are made of discrete cells
Describe the giant algae. (1)
How does it challenge the cell theory? (2)
- seem to be unicellular
- very large structures (≤10cm)
- challenges idea that larger organisms are always made of many tiny cells
What is the equation for magnification? (1)
I = AM Image = Actual x Magnification
Convert 1mm to micrometers and nanometers. (2)
1mm = 1,000 micrometers 1mm = 1,000,000 nanometers
Outline the functions of life. (7)
Metabolism - all the enzyme catalysed reactions within an organism or cell
Response - a reaction by the living organism to changes in the external environment
Homeostasis - maintaining a constant internal environment within tolerable limits
Growth - increasing in cell size or number of cells
Reproduction - producing offspring either sexually or asexually
Excretion - removing waste products of metabolism and other unimportant materials from an organism
Nutrition - obtaining food to provide energy and the materials needed for growth
Which two unicellular organisms are studied? (2, SPELLING)
- Paramecium
2. Chlamydomonas
Which organism is a heterotroph, Paramecium or Chlamydomonas? (1)
Paramecium is heterotrophic, Chlamydomonas is autotrophic
How does the Paramecium consume, and what does it feed on? (4/5)
- engulfs food particles in vacuoles
- also digests food in vacuoles
- nutrients get absorbed into the cytoplasm
- Paramecium feed on microorganisms
- eg. bacteria, algae, yeasts
How does the Chlamydomonas synthesise organic molecules? (2/3)
- it has a large chloroplast for photosynthesis
- CO2 can be converted into necessary compounds
- carbon compounds from other organisms can be absorbed too
- through cell membrane
What structures do Paramecium and Chlamydomonas have projecting out from the cell? (3)
Paramecium: beating cilia propels the cell as response to environment
Chlamydomonas: flagella moves the cell towards brighter regions (sensed by light-sensitive ‘eyespot’)
What type of reproduction (sexual/asexual) do Paramecium and Chlamydomonas carry out? (2)
Both carry out sexual and asexual reproduction
- though asexual is more common among Paramecium
