Cell Biology

Question 1

What does cell membrane do?

Answer 1

Holds the cell together, and controls what can and can’t enter the cell

Question 2

What is cytoplasm?

Answer 2

A jelly-like substance where chemical reactions inside the cell happen. It surrounds all the sub-cellular structures

Question 3

What is DNA?

Answer 3

Genetic material controlling the activities of the cell

Question 4

What are ribosomes?

Answer 4

Site of protein synthesis in the cell

Question 5

What is within an animal cell?

Answer 5

• mitochondria
• cytoplasm
• ribosomes
• nucleus

Question 6

What extra is in a plant cell?

Answer 6

• cell wall
• chloroplasts
• permanent vacuole

Question 7

What is the permanent vacuole?

Answer 7

Containing cell Sap which supports the structure of the cell

Question 8

What is the cell wall?

Answer 8

Made from cellulose + strengthens the cell

Question 9

What are chloroplasts?

Answer 9

Organelles containing green pigment (chlorophyll) which absorbs light energy for photosynthesis. Contains enzymes needed for photosynthesis

Question 10

What do bacterial cells never have?

Answer 10

Mitochondria, chloroplasts or a nucleus (they are prokaryotes)

Question 11

What do bacterial cells have instead of a nucleus?

Answer 11

A circular strand of DNA

Question 12

What are eukaryotic cells?

Answer 12

Cells with a nucleus (animal and plant cells)

Question 13

What are prokaryotic cells?

Answer 13

Cells without a nucleus but have genetic material in a single loop of DNA (bacterial cells)

Question 14

What are bigger , eukaryotic or prokaryotic cells?

Answer 14

Eukaryotic cells

Question 15

What is a specialised cell?

Answer 15

A cell that has a particular structure and composition of subcellular structures

Question 16

What is the process that cells specialise through?

Answer 16

Differentiation

Question 17

What is a cell called that hasn’t differentiated?

Answer 17

An unspecialised cell

Question 18

How do light microscopes form an image?

Answer 18

They use light and lenses.
It has two lenses (objective lense and eyepiece lense)

Question 19

What does the objective lense do in a light microscope?

Answer 19

It produces a magnified image and then the eyepiece lense directs the image to the eye

Question 20

What are microscopes used to see?

Answer 20

Tissues, cells, large sub-cellular structures

Question 21

What are the two types of microscopes?

Answer 21

Light and electron

Question 22

What do electron microscopes allow you to do that light microscopes don’t?

Answer 22

View deep inside sub-cellular structures e.g. mitochondria, ribosomes, chloroplasts and plasmids

Question 23

What are the two types of electron microscope?

Answer 23

• A scanning electron microscope (creates 3D images @ a slightly lower magnification)
• A transmission electron microscope (creates 2D images)

Question 24

Formula for magnification:

Answer 24

Magnification = image size ➗ real size

Question 25

Formula for the magnification of a light microscope

Answer 25

Magnification of a light microscope = magnification of the eyepiece lense x magnification of the objective lense

Question 26

How are sperm cells specialised?

Answer 26

They are specialised for reproduction
-has a long tail and a streamlined head helping it swim to the egg
- lots of mitochondria in cell to provide the energy needed
- carries enzymes in its head to digest through the egg cell membrane

Question 27

How are nerve cells specialised?

Answer 27

Specialised for RAPID SIGNALLING
function = carry electrical signals from one part of the body to another
- cells are long (cover more distance)
- have branched connections at their ends to connect to other nerve cells + form a network throughout the body

Question 28

How are muscle cells specialised?

Answer 28

They are specialised for CONTRACTION
Function of a muscle cell = to contract quickly
- cells are long (so that they have space to contract)
- contain lots of mitochondria (to generate energy needed for contraction)

Question 29

How are root hair cells specialised?

Answer 29

Specialised for absorbing water and minerals
- cells on the surface of plant roots which grow into long ‘hairs’ that stick out into the soil
- gives plant a big surface area for absorbing water + mineral ions from the soil

Question 30

How are xylem and phloem cells specialised?

Answer 30

Specialised for transporting substances
- the cells form phloem and xylem tubes, which transport substances such as food and water around the plant
- xylem cells are hollow in the centre and phloem cells have very few sub cellular structures so that stuff can flow through them