Topic 1 Cell Biology

Question 1

Define Active transport

Answer 1

The movement of substances from a more dilute solution to a more concentrated solution (against a concentration gradient) with the use of energy from respiration.

Question 2

Define Cell differentiation

Answer 2

The process where a cell becomes specialised to its function.

Question 3

Define Cell membrane

Answer 3

A partially permeable barrier that surrounds the cell.

Question 4

Define Cell wall

Answer 4

An outer layer made of cellulose that strengthens plant cells.

Question 5

Define Chloroplast

Answer 5

An organelle which is the site of photosynthesis.

Question 6

Define Chromosomes

Answer 6

DNA structures that are found in the nucleus which are made up of genes.

Question 7

Define Concentration gradient

Answer 7

The difference in concentration between two areas.

Question 8

Define Diffusion

Answer 8

The spreading out of the particles of any substance in solution, or particles of a gas, resulting in a net movement from an area of higher concentration to an area of lower
concentration.

Question 9

Define Embryonic stem cell

Answer 9

A type of stem cell that can differentiate into most types of human cells.

Question 10

Define Eukaryotic cell

Answer 10

A type of cell found in plants and animals that contains a nucleus.

Question 11

Define Magnification

Answer 11

How much bigger an image appears compared to the original object.

Question 12

Define Meristematic cells

Answer 12

A type of stem cell that can differentiate into any type of plant cell.

Question 13

Define Mitochondria

Answer 13

An organelle which is the site of respiration.

Question 14

Define Mitosis

Answer 14

A type of cell division which produces two genetically identical daughter cells from one parent cell.

Question 15

Define Nucleus

Answer 15

An organelle found in most eukaryotic cells that contains the genetic material of the cell and controls the activities of the cell.

Question 16

Define Organelle

Answer 16

A specialised structure found inside a cell.

Question 17

Define Osmosis

Answer 17

The diffusion of water from a dilute solution to a concentrated solution through a partially permeable membrane.

Question 18

Define Plasmid

Answer 18

Loops of DNA found in the cytoplasm of prokaryotic cells.

Question 19

Define Prokaryotic cell

Answer 19

A type of cell found in bacteria that does not contain a nucleus.

Question 20

Define Resolution

Answer 20

The ability to distinguish two different points in a specimen.

Question 21

Define Specialised cells

Answer 21

Cells that are adapted to perform a specific function.

Question 22

Define Stem cell

Answer 22

An undifferentiated cell that can divide to produce many specialised cells of the same type.

Question 23

Define Surface area

Answer 23

The amount of contact an object has with its environment.

Question 24

Define Surface area to volume ratio (SA:V)

Answer 24

The size of the object compared with the amount of area where it contacts its environment.

Question 25

Define The cell cycle

Answer 25

A series of stages preparing the cell for division.

Question 26

Define Therapeutic cloning

Answer 26

Producing an embryo that has the same genes as a patient.

Question 27

Define Vacuole

Answer 27

An organelle that stores cell sap.

Question 28

What are 2 types of cells

Answer 28

Eukaryotes Prokaryotes

Question 29

What is difference in eukaryotic and prokaryotic cells

Answer 29

Prokaryotic cells are much smaller and have no nucleus. Eukaryotes have a nucleus and are more complex.

Question 30

What do bacterial cells have instead of a nucleus

Answer 30

A single circular strand of DNA which floats freely in the cytoplasm. Some may also have one or more small rings of DNA called plasmids.

Question 31

When does most differentiation occur

Answer 31

As an organism develops. Ability to differentiate is lost at an early stage in humans but not plants.

Question 32

What is differentiation in mature animals mainly used for

Answer 32

Repairing and replacing cells e.g. skin and blood cells

Question 33

What are sperm cells specialised for

Answer 33

Reproduction

Question 34

What is the function of a sperm cell

Answer 34

To get the Male DNA to the Female DNA.

Question 35

List 4 ways sperm cells are adapted to its function

Answer 35

-Long tail for swimming -Streamlined head to help swim -Lots of mitochondria to provide energy for swimming -Carries enzymes in the head to digest through egg cell membrane.

Question 36

What are nerve cells specialised for

Answer 36

Rapid signalling

Question 37

What is the function of a nerve cell

Answer 37

To carry electrical signals from one part of the body to another

Question 38

How are nerve cells adapted for their function

Answer 38

Long - to cover more distance Branched connections at the ends - to connect to other nerve cells and form a network throughout the body.

Question 39

What are muscle cells specialised for

Answer 39

Contraction

Question 40

What is the function of a muscle cell

Answer 40

To contract quickly

Question 41

How are muscle cells adapted for their function

Answer 41

Long cells- space to contract Lots of mitochondria- to generate energy needed for contraction.

Question 42

What are root hair cells specialised for

Answer 42

Absorbing water and minerals

Question 43

How are root hair cells adapted for their function

Answer 43

Long hairs- Big surface area for absorbing water and mineral ions fromm the soil.

Question 44

What are root hair cells

Answer 44

They are cells on the surface of plant roots which grow into long hairs that stick out in the soil.

Question 45

What is the function of a xylem cell and what is the movement of water called

Answer 45

Transporting water and mineral ions from the roots to the stem and leaves. The movement through the xylem and out the leaves is called the transpiration stream.

Question 46

What is the function of a phloem cell and what process does it do

Answer 46

Transporting food (mainly dissolved sugars) made in the leaves to the rest of the plant for immediate use or storage. The transport goes in both directions which is called translocation.

Question 47

What are xylem cells made up of

Answer 47

They are made up of dead cells and strengthened with lignin.

Question 48

What are phloem cells made up of

Answer 48

They are made up of elongated living cells with small pores in the end walls allowing cell sap to flow through.

Question 49

Where can adult stem cells be found

Answer 49

In the bone marrow in the femur.

Question 50

How is therapeutic cloning used for medicine

Answer 50

Stem cells taken from the embryo to replace faulty cells in the patient can be used since it won't reject their body with the same genes.

Question 51

What is an advantage of stem cell research

Answer 51

Embryos used for reserach are usually unwanted ones from fertility clinics and are used instead of destroyed.

Question 52

List 3 ethical issues of stem cell research

Answer 52

- Human embryos are a potential life - Embryos cannot consent to research - Curing patients that exist is more important than rights of embryos

Question 53

Where are plant stem cells found

Answer 53

In the meristem

Question 54

List 3 advantages of plant cloning

Answer 54

-Produced quickly and cheaply -Grow rare species to prevent extinction -Grow desired features of plants for farmers crops.e.g. disease resistance.