Cell biology

Question 1

See animal cell flashcard

Answer 1

See animal cell flashcard

Question 2

See plant cell flashcard

Answer 2

See plant cell flashcard

Question 3

What are classified as eukaryotes and prokaryote

Answer 3

Eukaryotes:
Animal - two cells or more
Plant - two cells or more
Fungi - anything fungal (decomposes)
Protoctista (protoctist) - unicellular

Prokaryote:
Bacteria

Question 4

How is the sperm, nerve and muscle cell specialised (in animals)

Answer 4

Sperm cell:
Tail to help them swim
A large number of mitochondria to release energy from glucose to keep swimming

Nerve cell:
Sends electrical impulses around the body

Muscle cell:
Smooth muscles contract and relax automatically, e.g. iris
Cardiac muscles contract and relax automatically, e.g. heart
Skeletal muscle are attached to the bones and we control them

Question 5

How is the root hair, xylem and phloem cell specialised (in plants)

Answer 5

Root hair cell:
Thin extension which pokes into the soil to increase surface area which allows it to store more water and minerals from the soil

Xylem cell:
Carries water and dissolved materials from the roots and green parts
Reinforced side walls to support the weight of the plant (lignin)

Phloem cell:
Carries glucose made from photosynthesis from the leaves to other parts of the plant

Question 6

What is cell differentiation

Answer 6

The process during which young immature cells take on individual characteristics and reach their mature form and structure

Animal cells differentiate at an early stage
Plant cells retain the ability to do this

Question 7

What are the two types of microscopes and what are their properties

Answer 7

Light microscope:
Cheap and easy to use
Up to x2000 magnification
Resolving power of about 200 nm

Electron microscope:
Very expensive
Up to x2000000 magnification
Resolving power of about 0.2 nm

Question 8

What is the equation for magnification

Answer 8

magnification = size of image / size of real object

SBD - Small to big = Divide
BSM - Big to Small = Multiply

Question 9

How do you convert between cm, mm and µm

Answer 9

1 cm = 10 mm
1 cm = 10000 µm

1 mm = 0.1 cm
1 mm = 1000 µm

1 µm = 0.0001 cm
1 µm = 0.001 mm

Question 10

What is a chromosome

Answer 10

Carries genetic information in the form of genes, found in the nucleus

Question 11

What is the cell cycle

Answer 11

DNA synthesis - the chromosomes are now double strands
Further growth occurs and is checked for errors
Mitosis
The cytoplasm separated - two cells are formed
Temporary cell resting period or cell stops dividing
Cell growth

Question 12

What are the stem cells in animals

Answer 12

Embryotic stem cells:
Found in the embryo
Starts as an unspecialised cell
Stops a blastula from turning into an embryo

Adult Stem Cell:
Found in bone marrow
Generate less cells the ESC
Have more tissue than thought
Researchers are seeing if ASC can heal damaged organs

Umbilical Stem Cells:
Found in the umbilical cord
Can be treatment or blood disease

Question 13

What is therapeutic cloning

Answer 13

An embryo is produced with the same genes as the patient and the stem cells from the embryo aren’t rejected by the patients body so it can be used for medical treatment
Can cause infection
Ethical and religious objections

Question 14

What is the stem cell found in plants

Answer 14

Meristems
Found close to the shoot and root
Cell division occurs here
Can produce cell types of plant cells at any time during its life

Question 15

What are the factors that affect diffusion

Answer 15

Temperature
Surface area of membrane
Difference in concentrations (concentration gradient)

Question 16

How does diffusion work in the lungs

Answer 16

Oxygen is taken into the lungs which is then taken to an alveoli
Oxygen diffuses to the blood by the capillaries to make the distance shorter (high conc -> low conc = blood)
Once this goes round the body, CO2 diffuses back into the alveoli (low conc -> high conc = alveoli)
We breath out CO2

Question 17

What is passive diffusion

Answer 17

Involves atoms/molecules moving down a concentration gradients from a high concentration gradient to a low concentration gradient. This happens across a cell membrane

Question 18

What is osmosis

Answer 18

The passive diffusion of water going from a high water concentration to a low water concentration across a semi-permeable membrane

Question 19

What is active transport

Answer 19

The movement of dissolved chemicals from an area of low concentration to an area with high concentration against a concentration gradient. This involves movement across a membrane and it involve energy