1.1 Cell Structure Flashcards

Question

Describe how sperm cells in animals are adapted to their function. (4)

Answer 1

* **Haploid nucleus** contains genetic information. * **Tail** enables movement. * **Mitochondria** provide energy for tail movement. * **Acrosome** contains enzymes that digest the egg cell membrane.

Answer 2

* **Long axon** allows electrical impulses to be transmitted all over the body from the central nervous system. * **Dendrites** from the cell body connect to and receive impulses from other nerve cells, muscles and glands. * **Myelin sheath** insulates the axon and speeds up the transmission of impulses along the nerve cell.

Answer 3

* **Arrangement of protein filaments** allows them to slide over each other to produce muscle contraction. * **Mitochondria** to provide energy for muscle contraction. * **Merged cells in skeletal muscle** allow muscle fibre contraction in unison.

Answer 4

* **Large surface area** maximises rate of absorption of nutrients and water from surrounding soil. * **Thin walls** that do not restrict water absorption. * **Contain lots of mitochondria** which release energy for active transport of mineral ions.

Answer 5

* **Lignin-thickened walls** strengthen / support the structure and prevent collapse. * **No end walls between cells** allowing water and dissolved mineral ions to flow easily from the roots to the leaves by transpiration. * Made of **dead cells with no internal structures** providing a continuous route for water to flow.

Answer 6

* **Vessel cells (no nucleus and limited cytoplasm)** allow dissolved sugars to efficiently move through the cell interior. * **Sieve plates (end walls of vessels)** let dissolved amino acids and sugars translocate up and down the stem. * **Companion cells (connected to vessel cells)** have lots of mitochondria, providing energy to the vessel cell, which is needed for the active transport of substances.

Answer 7

The process by which cells become specialised.

Answer 8

Allows production of different tissues and organs that perform various vital functions in the human body.

Answer 9

Early in their life cycle

Answer 10

Throughout their entire life cycle

Answer 11

Repair and replacement of cells.

Answer 12

As a cell become specialised, it goes through the acquisition of different sub-cellular structures to enable specific functions to be performed by the cell.

Answer 13

The number of times bigger an image appears compared to the size of the real object.

Answer 14

The smallest distance between two objects that can be distinguished.

Answer 15

Passes a beam of light through a specimen which travels through the eyepiece lens, allowing the specimen to be observed.

Answer 16

* Inexpensive * Easy to use * Portable * Observe both dead and living specimens

Answer 17

Limited resolution power and magnification

Answer 18

1) It uses beams of electrons which are focused using magnets. 2) The electrons hit a fluorescent screen which emits visible light, producing an image.

Answer 19

Transmission electron microscope (TEM) Scanning electron microscope (SEM)

Answer 20

Greater magnification and higher resolution power.

Answer 21

They use a beam of electrons which has a shorter wavelength than photons of light.

Answer 22

* Allow small sub-cellular structures (e.g. mitochondria, ribosomes) to be observed in finer detail. * Enable scientists to develop more accurate explanations about how cell structure relates to function.

Answer 23

* Expensive * Large so less portable * Require training to use * Only dead specimens can be observed

Answer 24

Magnification = size of image / size of real object

Answer 25

A way of expressing numbers - written as a figure between 1 and 10 multiplied by a positive or negative power of 10.

Answer 26

0.005 ^{(3 jumps)} = 5 × 10⁻³

Answer 27

10382 ^{(4 jumps)} = 1.0382 × 10⁴

Answer 28

* Stage * Clips * Objective lenses (3) * Eye piece (consists of an eye piece lens) * Fine focussing dial * Coarse focussing dial * Lamp / mirror

Answer 29

1. Organism 2. Cell 3. Nucleus 4. Chromosome 5. Gene 6. DNA

Answer 30

* Capsule * Cell wall * Plasma membrane * Cytoplasm * Plasmid * Ribosome * Nucleoid (DNA) * Bacterial flagellum

Answer 31

Binary fission (simple cell division)

Answer 32

Once every 20 minutes if enough nutrients are available and the temperature is suitable.

Answer 33

* Nutrient broth solution * Colonies on an agar gel plate

Answer 34

Nutrients required for bacteria growth; For example * Carbohydrates (for energy). * Nitrogen (for protein synthesis). * Glucose (for respiration). * Amino acids (for protein → growth). * Other mineral ions.

Answer 35

Investigating disinfectant and antibiotic action.

Answer 36

1. Wipe workspace with disinfectant. 2. Heat inoculating loop in the flame and allow to cool down. 3. Open lid of the bottle slightly to insert the loop - quickly replace lid. 4. Open lid of the Petri dish slightly and spread the loop on the surface. 5. Quickly close lid of Petri dish then seal securely with tape. 6. Incubate upside down in an oven at 25ºC to allow growth of bacteria.

Answer 37

To kill any present, and prevent growth of, unwanted bacteria.

Answer 38

To kill unwanted microorganisms present on the loop.

Answer 39

* It prevents unwanted bacteria in the air entering the culture. * The lid is not fully sealed so that anaerobic bacteria won't grow.

Answer 40

Harmful bacteria are more likely to grow at a higher temperature.

Answer 41

πr² | [π = 3.14 | r = radius | r = diameter ÷ 2]

Answer 42

1. Ensure both times (mean division time and the time dividing) are of the same units. 2. Calculate the number of divisions by doing: time dividing / mean division time. 3. Multiply the current population by 2 to the power of the number of divisions to find the number of bacterial cells produced.

Answer 43

To sterilise/kill unwanted microorganisms.

Answer 44

To reduce contamination of unwanted bacteria entering from surrounding air.

Answer 45

To prevent condensation from forming and dripping down onto the colonies.

Answer 46

1. _Convert total division time._ Total division time = 3 (hours) × 60 mins = 180 mins 2. _Calculate number of divisions._ Number of divisions = 180 (mins) ÷ 15 (mins) = 12 3. _Calculate number of bacteria._ Number of cells = 5 × 2¹² = _20480 bacteria_ or _2.048 × 10⁴ bacteria_ | Number of divisions = Total division time (mins) ÷ Mean division time (mins) Number of bacteria = Current bacteria × 2^{number of divisions}

Answer 47

1. _Convert total division time._ Total division time = 2 hours × 60 mins = 120 mins 2. _Calculate number of divisions._ Number of divisions = 120 mins ÷ 40 mins = 3 3. _Calculate number of cells._ Number of cells = 1 × 2³ = _8 cells_ | Number of divisions = Total division time (mins) ÷ Mean division time (mins) Number of bacteria = Current bacteria × 2^{number of divisions}

Answer 48

1. Number of divisions = Total division time (mins) ÷ Mean division time (mins) 2. Number of bacteria = Current bacteria × 2^{number of divisions} _OR_ 1. Number of divisions = Total division time (hours) ÷ Mean division time (hours) 2. Number of bacteria = Current bacteria × 2^{number of divisions}

Answer 49

Hours = number of minutes ÷ 60 Minutes = number of hours × 60

Answer 50

1. _Convert total division time._ Total division time = 3 hours x 60 mins = 180 mins 2. Calculate number of divisions._ Number of divisions = 180 / 20 = 9 3. _Calculate number of cells._ Number of cells = 2⁹ = _512 cells_ | Number of divisions = Total division time (mins) ÷ Mean division time (mins) Number of bacteria = Current bacteria × 2^{number of divisions}

Answer 51

1. _Convert total division time._ Total division time = 24 hours × 60 mins = 1440 mins 2. Calculate number of divisions._ Number of divisions = 1440 / 20 = 72 3. _Calculate number of cells._ Number of cells = 300 × 2⁷² = _1.45 × 10_²⁴ _cells_ | Number of divisions = Total division time (mins) ÷ Mean division time (mins) Number of bacteria = Current bacteria × 2^{number of divisions}

1.1 Cell Structure Flashcards

Completed | T1 Cell Biology | physicsandmathstutor (75 cards)