CELL BIOLOGY

Question 1

What type of cell doesn’t have a nucleus?

Answer 1

Prokaryote

Question 2

What does the nucleus do?

Answer 2

Contains genetic material that controls activities in the cell

Question 3

What does the cytoplasm do?

Answer 3

Where most of the chemical reactions happen (contains enzymes)

Question 4

What does the cell membrane do?

Answer 4

Holds the cell together and controls what goes in and out

Question 5

What do the mitochondria do?

Answer 5

Where aerobic respiration occurs so energy is transferred (powerhouse of the cell)

Question 6

What do the ribosomes do?

Answer 6

Where proteins are made

Question 7

What does a rigid cell wall do?

Answer 7

Made of cellulose and supports/strengthens the cell

Question 8

What do vacuoles do?

Answer 8

Contain cell sap (weak solution of sugar and salts)

Question 9

What do chloroplasts do?

Answer 9

Where photosynthesis occurs which makes food for plants (contains green substance called chlorophyll which absorbs light)

Question 10

What don’t bacteria have?

Answer 10

Mitochondria
Nucleus
Chloroplasts

Question 11

What do bacteria cells have instead of a nucleus?

Answer 11

A singular stand of DNA that freely floats in the cytoplasm (+ plasmids small rings of DNA)

Question 12

What type of cell is bacteria?

Answer 12

Prokaryote

Question 13

What are light microscopes?

Answer 13

Use light and lenses to form an image
We can see individual cells and large subcellular structures

Question 14

What are electron microscopes?

Answer 14

Use electrons
Have a much higher magnification and resolution than light microscopes

Question 15

How do you calculate magnification?

Answer 15

Image size / real size

Question 16

What is cell differentiation?

Answer 16

When a cell changes to become specialised for its job
They develop different subcellular structures to carry out of different functions

Question 17

What are stem cells?

Answer 17

Undifferentiated cells

Question 18

What is the function of a sperm cell?

Answer 18

To get the male DNA to the female DNA
Long tail and streamlined heard to swim to the egg
Lots of mitochondria for energy
Enzymes in head to digest through the egg cell membrane

Question 19

What is the function of a nerve cell?

Answer 19

To carry electrical signals from one part of the body to another
Long to cover more distance
Branched connections to connect with other nerve cells

Question 20

What is the function of a muscle cell?

Answer 20

To contract quickly
Long so they have space to contract
Lots of mitochondria to generate lots of energy to contract

Question 21

What is the function of root hair cells?

Answer 21

To absorb water and minerals
Big surface area for absorbing nutrients from the soil

Question 22

What are the functions of phloem and xylem cells?

Answer 22

To transport food and water around plants
Xylem cells are hollow and phloem cells have very few subcellular structures so stuff can flow through them

Question 23

What are chromosomes and where are they found?

Answer 23

They are coiled up lengths of DNA found in the nucleus

Question 24

What do genes do and where are they found?

Answer 24

They control the development of different characteristics and are found in chromosomes

Question 25

How many pairs of chromosomes do humans have?

Answer 25

23

Question 26

What is mitosis?

Answer 26

When body cells divide to produce new cells

Question 27

Why does mitosis take place?

Answer 27

To grow and replace cells that have been damaged

Question 28

What is produced after the cell cycle?

Answer 28

Two new daughter cells are formed identical to the original cell with the same number of chromosomes in each

Question 29

What happens in the growth and DNA replication stage of the cell cycle?

Answer 29

The cell grows and increases the amount of subcellular structures it has It then duplicates its DNA (forms x-shaped chromosomes)

Question 30

What happens during mitosis in the cell cycle?

Answer 30

Chromosomes line up a the centre and cell fibres pull them apart (split a pair of chromosomes into two) to different sides of the cell Membranes form around the new set of chromosomes Then the cytoplasm and cell membrane divide

Question 31

What is binary fission?

Answer 31

When a prokaryotic cell splits in two

Question 32

What happens during binary fission?

Answer 32

DNA and plasmids replicate Cell gets bigger and DNA strands move to opposite sides of the cell Cytoplasm divides New cell walls form Two daughter cells are produced

Question 33

What is a cultured medium?

Answer 33

An environment where a bacteria has all the carbohydrates, minerals, proteins and vitamins it needs to grow

Question 34

Where are most stem cells found in adults?

Answer 34

Bone marrow

Question 35

What is the difference between adult stem cells and embryonic stem cells?

Answer 35

Adult stem cells can't turn into any type of cells only certain ones like red blood cells

Question 36

Why are some people against stem cell research?

Answer 36

Kills the embryo

Question 37

How can stem cells produce identical plants?

Answer 37

In the meristems stem cells are found and they can produce clones of whole plants quickly and cheaply

Question 38

What is diffusion?

Answer 38

The gradual movement of particles from an area of high concentration to an area of low concentration along the concentration gradient (passive)

Question 39

Why does diffusion happen in liquids and gases?

Answer 39

Because the particles are free to move

Question 40

How does temperature affect the rate of diffusion?

Answer 40

Higher temp means faster diffusion rate because the particles have more energy so they are moving around faster

Question 41

What can diffusion do?

Answer 41

Move dissolved substances through cell membranes and into a cell

Question 42

How does surface area affect the rate of diffusion?

Answer 42

The bigger the surface area the more particles can go through at once so increased rate of diffusion

Question 43

What is osmosis?

Answer 43

The movement of water molecules across a partially permeable membrane from an area of high concentration to an area of low concentration with the concentration gradient (passive)

Question 44

What is a partially permeable membrane?

Answer 44

A membrane with very small holes in it

Question 45

What is active transport?

Answer 45

The movement of molecules from an area of low concentration to an area of high against the concentration gradient (active)

Question 46

How do root hair cells use active transport?

Answer 46

Because there is a higher concentration of minerals (molecules) in the root hair cell, to absorb more minerals they have to travel against the concentration gradient Needs energy from respiration

Question 47

How do we use active transport in our body?

Answer 47

Nutrients (glucose) from the gut are taken into the blood where there is a higher concentration of nutrients (can happen both ways D or AT)

Question 48

How does urine and diffusion relate?

Answer 48

Urea diffuses from cells into the blood plasma for removal by the kidneys

Question 49

What is the difference between single-cellular organisms surface area and multi-cellular organisms?

Answer 49

Single-cellular organisms have a larger surface area so more substances can diffuse into the cell

Question 50

What are exchange surfaces adapted for diffusion/active transport?

Answer 50

Thin membrane so substances only have to diffuse in a short distance Large surface area so lots of the substance can diffuse at once

Question 51

How are the alveoli fit for diffusion?

Answer 51

Large surface area Moist lining for dissolving gases Thin walls so less distance Good blood supply

Question 52

How are villi in the small intestine fit for diffusion?

Answer 52

Large surface area so digested food is absorbed into the blood more quickly

Question 53

How do plants diffuse carbon dioxide for photosynthesis?

Answer 53

Underneath the leaf there is an exchange surface Holes called stomata with guard cells Flattened shape of the leaf increases area