cell biology

Question 1

what is the order of cell size?

Answer 1

• cell
• tissue
• organ
• organ system
• organism

Question 2

what does an animal cell contain?

Answer 2

• Nucleus
• Cytoplasm
• Cell membrane
• Mitochondria
• Ribosomes

Question 3

what does a plant cell contain?

Answer 3

• Nucleus
• Cytoplasm
• Cell membrane
• Mitochondria
• Ribosomes
• Cell wall
• Permanent vacuole
• Chloroplasts

Question 4

what is the nucleus?

Answer 4

contains genetic material, controls the activities of the cell

Question 5

what is the cytoplasm?

Answer 5

gel like substance where most of the chemical reactions happen. It contains enzymes that control the reactions

Question 6

what is the cell membrane?

Answer 6

holds the cell together and controls what goes in and out the cell

Question 7

what is the mitochondria?

Answer 7

these are where most of the aerobic respiration take place

Question 8

what are the ribosomes?

Answer 8

these are where proteins are made in the cell

Question 9

what is the cell wall?

Answer 9

made of cellulose, supports and strengthens the cell

Question 10

what are the chloroplasts?

Answer 10

these are where photosynthesis occurs, contains chlorophyll which absorbs the light needed for photosynthesis.

Question 11

what is the vacuole?

Answer 11

stores water to keep the plant turgid (firm)

Question 12

what do prokaryotic cells contain?

note: prokaryotic cells use binary fission for cell division

Answer 12

• cytoplasm
• cell membrane
• cell wall
• singular circular - strand of DNA
• plasmids (small rings of DNA)

Question 13

Give an example of a prokaryotic cell:

Answer 13

bacterial cell

Question 14

what do eukaryotic cells contain?

note: eukaryotic cells use mitosis for cell division

Answer 14

• cell membrane
• cell wall (sometimes)
• cytoplasm
• ribosomes
• chloroplasts
• mitochondria
• nucleus

Question 15

Give an example of an eukaryotic cell:

Answer 15

Plant cells or animal cells

Question 16

how to calculate magnification?

Answer 16

magnification = image size/real size

Question 17

name some specialized cells:

Answer 17

1) sperm cells - reproduction
2) nerve cells - rapid signaling
3) muscle cells - contraction
4) root hair cells - absorbing water and minerals
5) phloem/xylem - transporting substances in plants

Question 18

what are chromosomes?

Answer 18

chromosomes contain genetic material, They are coiled up pieces of DNA molecules, each chromosome contains a large number of genes.

Question 19

describe growth & DNA replication:

Answer 19

• in a cell that is dividing, the DNA is spread out in long strings
• the cell has to grow and increase the amount of subcellular structures such as mitochondria and ribosomes
• it then duplicates its DNA - one copy for each new cell
• the DNA is copied and forms X shaped chromosomes.

Question 20

describe the process of Mitosis:

Answer 20

• the chromosomes line up at the centre of the cell and cell fibres pull them apart.
• The two arms of each chromosomes go to opposite ends of the cell
  membranes form around each of the sets of chromosomes.
• These become the nuclei of the new cells. the nucleus has split.
• lastly, the cytoplasm and cell membrane divide
• the cell has now produced 2 daughter cells, which are identical.

Question 21

Describe the process of binary fission:

Answer 21

• prokaryotic cells replicate using binary fission
• the circular DNA and plasmids replicate
• the cell gets bigger and the strands move to opposite poles of the cell
• the cytoplasm begins to divide and new cell walls form
• the cytoplasm divides and two daughter cells are produced
• each cell has one copy of the circular DNA but they can have a variable number of copies of the plasmid(s)

Question 22

Describe stem cells:

Answer 22

• embryonic stem cells can turn into any type of cell
• stem cells may be able to cure many diseases
• some people are against stem cell research
• stem cells can produce identical plants

Question 23

give a reason for stem cell transplants:

Answer 23

• can be used to replace faulty cells
• in a type of cloning, therapeutic cloning, an embryo could be made to have the same genetic information as the patient (cannot be rejected)

Question 24

give a reason against stem cell transplants:

Answer 24

• they feel the human embryos shouldn’t be used as it is a potential human life
• it provides a health risk to everyone involved
• It isn’t cheap and we don’t know the long term affects

Question 25

how are stem cells used to produce plant cells?

Answer 25

- stem cells are in the meristems (Where growth occurs) - during the plant's life, cells in the meristem tissues can change into any type of plant cell - they can be used to grow more plants of rare species - can also be used to grow crops with specific features for farmers

Question 26

What is diffusion?

Answer 26

Diffusion is the SPREADING OUT of particles from an area of HIGHER concentration to an area of LOWER concentration

Question 27

what is osmosis?

Answer 27

osmosis is the movement of water molecules across a partially permeable membrane from a region of higher water concentration to a region of lower water concentration

Question 28

What is active transport?

Answer 28

Active transport is when a substance needs to be absorbed against a concentration gradient.

Question 29

what happens during gas exchange in the lungs?

Answer 29

- the lungs transfer oxygen to the blood and remove waste carbon dioxide from it - to do this, the lungs contain millions of little air sacs (Alveoli) where gas exchange takes place

Question 30

Give another example of exchanging substances:

Answer 30

- the villi provide a really big surface area inside the small intestine. - They increase the surface area so that digested food is absorbed more quickly - The structure of leaves lets gases diffuse in and out of cells - Gills have a large surface area for gas exchange