Chapter 1: Cell structure

Question 1

How large is a bacterium?

Answer 1

1 to 10 micrometers long

Question 2

What is a plasmid?

Answer 2

A small ring of free-floating DNA found in prokaryotic cells (cells without a nucleus such as bacteria)

Question 3

What is cytoplasm?

Answer 3

Cell fluid (mostly water). Reactions happen here

Question 4

What is a cell wall?

Answer 4

A wall that provides support for the cell, found in bacteria, plants (made of cellulose) and fungi

Question 5

What is the cell membrane?

Answer 5

The membrane surrounding the cell that controls what substances go in and out of a cell. It also has internal extensions with enzymes attached to them, where respiration occurs

Question 6

What are ribosomes?

Answer 6

Protein factories, which are suspended in the cytoplasm

Question 7

What is diffusion?

Answer 7

Net movement of particles from an area of high concentration to an area of lower concentration

Question 8

What are mitochondria?

Answer 8

Small organelles found in the cytoplasm of eukaryotic cells where respiration takes place

Question 9

What is a nucleus?

Answer 9

An organelle found in eukaryotic cells where chromosomes are located

Question 10

What are chromosomes?

Answer 10

Structures containing DNA

Question 11

What are chloroplasts?

Answer 11

Components of plant cells where light is absorbed and photosynthesis takes place

Question 12

What is the vacuole?

Answer 12

The area in the middle of a plant cell full of sap, which keeps the cell turgid

Question 13

How are sperm cells adapted to their purpose?

Answer 13

Their tails and large numbers of mitochondria help them swim,

Question 14

How are nerve cells adapted to their purpose?

Answer 14

The myelin sheath insulates the electrical impulse, speeding up the electrical impulse. The many long extensions form junctions with other cells

Question 15

How are muscle cells adapted to their function?

Answer 15

They contain large numbers of mitochondria

Question 16

What are the 3 types of muscle cell?

Answer 16

Skeletal (manual), cardiac and smooth (automatic)

Question 17

How are root hair cells in plants adapted to their function?

Answer 17

They have a thin extension sticking out into the soil, increasing the surface area for water and mineral absorption

Question 18

What is a xylem?

Answer 18

A tube formed of dead plant cells joined together through which water flows during transpiration

Question 19

What is transpiration?

Answer 19

The gradual release of water vapor from leaves to continue the “pull” off water up from the soil

Question 20

How are xylem cells adapted to their function

Answer 20

Cell walls strengthened with lignin

Question 21

What are phloem cells?

Answer 21

Living cells that carry sugars made in photosynthesis to all cells of a plant

Question 22

What is translocation?

Answer 22

Movement of sugars around a plant

Question 23

How are phloem cells adapted for their purpose?

Answer 23

Fewer organelles, allowing sugars to travel easily, sieve plates

Question 24

What is cell differentiation?

Answer 24

The process in which generic cells turn into specialised adapted cells (such as muscle cells). This process happens continually in plants but only in the uterus in mammals

Question 25

How is total magnification calculated?

Answer 25

Magnification of objective lens * magnification of eyepiece lens

Question 26

Name the lenses in a light microscope

Answer 26

Eyepiece lens: The lens you look through
Objective lens: 3 lenses to choose from

Question 27

Name the different focuses

Answer 27

Course focus: Quickly moves the stage up and down
Fine focus: Slowly and sensitively moves the stage up and down

Question 28

How do scanning electron microscopes work?

Answer 28

They fire a small beam of electrons at a thin slice of the specimen. The beam scans across the image slowly. Electrons scatter from the surface of the sample and are detected to make an image

Question 29

How do scanning electron microscopes work?

Answer 29

They fire a small beam of electrons at a full specimen (not just a thin slice). The beam scans across the image slowly. Electrons scatter from the surface of the specimen and are detected to make an image

Question 30

How do transmission electron microscopes work?

Answer 30

They fire a huge beam of electrons at a thin slice of the specimen and detect the ones that make it through

Question 31

What is the difference between the images formed by scanning and transmission electron microscopes?

Answer 31

Scanning electron microscopes create 3D-looking images, transmission electron microscopes create images of 2D cross-sections. They both produce monochrome images

Question 32

What is the difference between light and electron microscopes?

Answer 32

Light microscopes are cheaper and lower resolution