Cells as the Basis of Life

Question 1

Nucleus: structure and function

Answer 1

Membrane bound, contains DNA

Contain genetic instructions for cell growth, repair and functioning

Question 2

Nucleolus: structure and function

Answer 2

Made of protons and RNA (in the nucleus)

Makes ribosomes

Question 3

Ribosomes: structure and function

Answer 3

Made of protein and RNA

Make proteins

Question 4

Endoplasmic Reticulum: structure and function

Answer 4

Network of flat, interconnected membranes
Rough ER: HAS ribosomes
Smooth ER: NO ribosomes

Rough ER: processes and modify proteins
Smooth ER: make lipids

Question 5

Golgi body

Answer 5

Flat, membrane-bound sacs that aren’t connected to each other

Processes and packages substances made in the cell, e.g: proteins

Question 6

Lysosomes

Answer 6

Membrane-bound vesicle that contains digestive enzymes

Breaks down cellular waste and forge in particles

Question 7

Cell definition

Answer 7

A cell refers to the smallest structural and functional unit of a living organism

Question 8

Organelles definiton

Answer 8

Membrane-bound coparents within the cell (have their own function)

Question 9

Chloroplasts: Function and structure

Answer 9

Disk-shaped with a double membrane, DNA and chlorophyll

Use light energy, carbon dioxide and water to produce glucose via photosynthesis

Question 10

Mitochondria: Function and structure

Answer 10

Have a double membrane (inner membrane highly folded) and DNA

Use oxygen and glucose to produce ATP (via respiration)

Question 11

Cell membrane: Function and structure

Answer 11

Flexible, semi-permeable membrane

Protect/contain organelles and control movement of substances in/out oil cell

Question 12

Cell wall: Function and structure

Answer 12

External structure which surrounds cell membrane (composition varies)

Structural strength and protection)

Question 13

Cytoplasm: Function and structure

Answer 13

Watery, gel-like fluid

Suspends organelles, give the cell shape

Question 14

Centrioles: Function and structure

Answer 14

A pair of small, cylindrical structures made of microtubules

Movement

Question 15

Vacuole: Function and structure

Answer 15

Membrane-bound, fluid-filled vesicle

Store substances; turgor pressure maintains shape/structure in plants

Question 16

The Fluid Mosaic model structure and fucntion

Answer 16

Cell membranes are phospholipid bilayers = 2 layers of phospholipid molecules (hydrophilic phosphate head and 2 hydrophobic lipid tails). Scattered through are carbohydrates, cholesterol and proteins

Main function of the cell membrane:

1. Seperate the cytoplasm from the external environment (all cells) and create organelles (only eukaryotes)
2. Regulate the movement of substances
3. Communicate and recognise

Question 17

Prokaryotes and Eukaryotes

Answer 17

Prokaryotic DOES NOT have a nucleus and membrane-bound organelles

Eukaryotic HAS a nucleus and membrane-bound organelles

Question 18

Rules for biological drawing

Answer 18

Materials
Positioning 
Size 
Accuracy 
Labels 
Title
Scale

Question 19

Light Microscope

Answer 19

• A light microscope uses light and 2 lenses( ocular and objective) to make the specimen look bigger
• It works by passing light through the specimen; this light is then reflected
• A specimen might be a: whole organism, smear of cells, thin slice of tissue
• We use staining techniques to help us see different cell structures more clearly

The confocal microscope is an example of an advanced light microscope

• It uses a laser to focus light on a very small section of the specimen
• This is used to create an image of the section
• The images produced are then stitched together to form a higher quality, 3D image

Magnification = Magnified size/ Actual size

Question 20

Electron Microscope

Answer 20

1. An electron gun shoots a beam of electrons at the specimen (in a vacuum)
2. These electrons interact with the specimen and bounce everywhere
3. Detectors measure the ricochet and a computer uses this information ro make an electron micrograph

Question 21

Diffusion

Answer 21

1. Passive: Movement of materials across the cell embrace WITHOUT the expenditure of energy
2. Diffusion: Movement of any material from high to low concentration
3. Simple: Though a phospholipid bilayer
4. Facilitated: Though selective channel and carrier proteins

Question 22

Osmosis

Answer 22

Osmosis refers to the movement of water form an area of high water concentration to an area of low water concentration across a semipermeable membrane

isotonic solutions- equal solute concentrations
A hypotonic solution- lower solute concentration
A hypertonic solution- higher collate concentration

Question 23

Differences between osmosis and diffusion

Answer 23

Osmosis exclusively refers to movement of water across a semipermeable membrane, whilst. diffusion is the movement of any material and doesn’t have ti involve a semipermeable membrane

Question 24

Active Transport

Answer 24

1.Movementof materials across the cell membrane that does require the expenditure of energy
2.
- Individual uses. carrier proteins to move individual molecules from low to high concentrations
- Bulk uses vesicles to move materials which are too big or when there’s too much
3.Endocytosis:move materials in cel
Exocytosis: Move materials out of cell.

Question 25

Factors Affecting the Rate of Exchange

Answer 25

The stopper the concentration gradient, the: - Faster the material will move towards the area of low concentration in passive transport - Slower the material will move towards the area of high concentration in active transport (unless the cell uses more energy) A the size of an object. decrease, its SA:V ration increases Bigger SA:V ratio = move efficient movement of materials across the cell membrane. 2 main strategies to increase SA:V ratio: 1.Flattened shape 2. Cell membrane extensions The smaller the particles, higher the temperature, the higher the rate of dissuasion

Question 26

Cell Requirements

Answer 26

- All cells need ATP energy to preform the rwcatiojs they need to survive Cells make ATP using energy from the breakdown of food there are 2 groups of organisms based on how they get food: 1. Autotroph- Organism, which uses energy and inorganic compounds too make its own food e.g: plants, algae and some bacteria 2. Heterotroph- organisms that can't make its own food and so it gets its nutrients by. consuming other organisms, e.g: animals, most bacteria, protists

Question 27

Waste Removal

Answer 27

Its important to ensure waste products are removed Bec use they can interrupt normal functioning Destroy cellular structures e.g: CO2 and nitrogenous wastes Take up space impact osmoregulation e.g: water Cellular level: applies to all calls - Passive removal- carbon dioxide, alcohol, ammonia, urea and water - Active removal- nitrogenous wastes, ions and most other toxins Body system level- Applies to multicellular organisms: plants- leaves release gaseous CO2 & H2O; other water via old leaves, bark and soil Animals- ;lungs release gaseous CO2 &H20; liver processes water, kidney filters blood and removes it

Question 28

Photosynthesis

Answer 28

Photosynthesis is the processes by which plants use sunlight to make their own organic compounds Carbon dioxide → water → sunlight → glucose + oxygen 1. Light-Dependent occur in the thylakoids Chlorophyll captures light energy (from the sun) → light energy is used to break water down into oxygen and hydrogen 2. Light-Independent occur in the stream ATP energy used ti combine carbon dioxide with hydrogen → glucose is produced The rate of photosynthesis is affected by a combination light intensity, CO2 levels and temperature

Question 29

Enzymes

Answer 29

Enzymes are biological catalysts Proteins that speed up the chemical reactions occurring inside cells (without. being use dup in the process) Enzymes are very sensitive- their activity is affected by temperature, PH and substrate concentration

Question 30

Pinocytosis

Answer 30

takes in fluids and soultues

Question 31

Phagocytosis

Answer 31

Takes in larger substances (bascteria)

Question 32

Receptor-mediated endocytosis

Answer 32

absorb metabolites, hormones, proteins

Question 33

Allelopathy

Answer 33

Allelopathy is a biological phenomenon by which an organism produces one or more biochemicals that influence the germination, growth, survival, and reproduction of other organisms. These biochemicals are known as allelochemicals and can have beneficial or detrimental effects on the target organisms and the community. Trees are great examples of allelopathy in plants. For instance, many trees use allelopathy to protect their space by using their roots to pull more water from the soil so other plants cannot thrive. ... Other trees that are known to exhibit allelopathic tendencies include maple, pine, and eucalyptus