Cells

Question 1

Specialised cells

Answer 1

Have adaptations which help them carry out a specific function

Question 2

Differentiation

Answer 2

The process in which a cell becomes specialised

Question 3

Sperm cell job

Answer 3

Join with an egg cell in fertilisation
To combine genetic information

Question 4

Sperm cell adaptations

Answer 4

Contain half genetic information in their nucleus
Long tail to swim to ovum
Packed with mitochondria = energy to swim
Enzymes at top of head to digest outer layer of ovum

Question 5

Nerve cell function

Answer 5

Send electrical impulses around the body via the axon (long stick bit)

Question 6

Nerve cell adaptations

Answer 6

Axon insulated by MYELIN to speed up transmission of nerve impulses
Has synapses for impulses to pass from one nerve to next
Dendrites to increase surface area = connect easier

Question 7

Muscle cell jobs

Answer 7

Can contract for movement

Question 8

Muscle cell adaptations

Answer 8

Protein fibres to change length (shorten) when contracted = decrease length of cell
Packed with mitochondria to provide energy via respiration
Form muscle tissue together

Question 9

Root hair cells job

Answer 9

Increase surface area of the root by acting as hairs to absorb water + minerals more effectively

Question 10

Root hair cell adaptations

Answer 10

Root hair to increase surface area
No chloroplasts because don’t photosynthesise

Question 11

Xylem cells job

Answer 11

Found in stem as long tubes
Carry water and dissolved minerals from roots to leaves

Question 12

Xylem cells adaptations

Answer 12

Thick walls w lignin to support the plant
Dead xylem cells because they’re sealed by lignin
Broken down end walls to from the long tube so minerals can flow easily
No internal structure (nucleus, cytoplasm, vacuole) = water and minerals flow easily

Question 13

Phloem cells job

Answer 13

Carry dissolved sugars up and down the plant

Question 14

Phloem cells structure

Answer 14

Phloem vessel cell
Sieve plates at end walls with pores
Companion cells connected by pores

Question 15

Phloem cells adaptations

Answer 15

Vessel cell have no nucleus only limited cytoplasm and sieve plates with pores at end so sugars move through interior
Companion cells with mitochondria to respire for energy = can move the sugars

Question 16

Eukaryotes

Answer 16

Cells that contain genetic information enclosed in a nucleus

Question 17

What are the common features of ALL eukaryotes?

Answer 17

Nucleus
Cell membrane
Cytoplasm
Usually larger than prokaryotes

Question 18

Eukaryotes examples

Answer 18

Animal cells + plant cells

Question 19

Prokaryotes

Answer 19

Genetic material isn’t enclosed in a nucleus

Question 20

How is genetic information arranged in a prokaryote?

Answer 20

A single loop of DNA
And maybe small rings called plasmids

Question 21

What are common features of prokaryotes? (Bacteria)

Answer 21

Smaller than eukaryotes
Genetic info in a loop and plasmids (non membrane organelles)
Cell membrane and cell wall
Cytoplasm
Divide by binary fission

Question 22

Stem cells

Answer 22

Undifferentiated cell that can divide to from more stem cells
And can differentiate to form specialised cells

Question 23

Embryonic stem cells

Answer 23

Stem cells formed when a zygote begins to divide and form other stem cells
Haven’t differentiated yet but can to form any type of specialise cell

Question 24

Adult stem cells

Answer 24

Stem cells that are present in non embryos but limited in differentiation

Question 25

Where can adult stem cells be found?

Answer 25

Bone marrow Eyes Brain Blood

Question 26

Bone marrow transplants (leukaemia)

Answer 26

Cancer of bone marrow Use radiation to destroy existing bone marrow Transplant bone marrow from donor Stem cells in bone marrow divide = new bone marrow Differentiate to from new blood cells

Question 27

Problems with bone marrow transplant

Answer 27

Donor must be compatible otherwise WBCs produced by transplanted marrow might attack patients body Risk of viruses passing

Question 28

Therapeutic cloning

Answer 28

Producing an embryo with same genetic information as patient to create embryonic stem cells That can be transferred then differentiated to replace harmed cells in the patient

Question 29

Therapeutic cloning steps

Answer 29

Egg cell from donor with no nucleus + nucleus from patient with their genetic info = egg cell stimulated to divide = embryo Remove stem cells for therapeutic use

Question 30

Benefits of therapeutic use

Answer 30

With the same genetic make up of patient = no rejection from the patients immune system Can differentiate into any cell type

Question 31

Uses of therapeutic cloning

Answer 31

Treating paralysis Type 1 diabetes

Question 32

Clinical problems with using stem cell medication

Answer 32

Mutations observed in cultured stem cells, behave like cancer Difficulty in storing embryonic stem cells No guarantee it’s successful

Question 33

Ethical issues using stem cell medication

Answer 33

Embryos may become viewed as a commodity and not treated with respect At what stage can an embryo be considered a person?

Question 34

Social issues using stem cells

Answer 34

Many studies about stem cells are by commercial clinics = not peer reviewed Patients exploited as it’s expensive and not certain it will work

Question 35

Cell cycle

Answer 35

Series of stages a cell goes through growing + dividing

Question 36

Nucleus function

Answer 36

Enclose genetic material

Question 37

Cytoplasm function

Answer 37

Where chemical reactions take place eg first stages of respiration

Question 38

Cell membrane function

Answer 38

Controls what molecules leave and enter the cell

Question 39

Mitochondria function

Answer 39

Where aerobic respiration takes place

Question 40

Ribosomes function

Answer 40

Sites of protein synthesis

Question 41

What do you need to use to see ribosomes and mitochondria?

Answer 41

Electron microscope Because they are very small

Question 42

What type of shape do plant cells have?

Answer 42

A regular one Can’t easily change it like animal cells

Question 43

Chloroplasts function

Answer 43

Contain chlorophyll (site of photosynthesis)

Question 44

Cell wall function

Answer 44

Made of cellulose To strengthen the cell so if receives too much water won’t burst

Question 45

Vacuole function

Answer 45

Permanent, filled with cell sap Helps give the plant shape

Question 46

Chromosomes

Answer 46

In pairs of 23 in a normal animal cell So 46 in total

Question 47

What do chromosomes contain?

Answer 47

Many genes

Question 48

What is the cell cycle?

Answer 48

We have so many cells so they must be able to divide = cell cycle

Question 49

Stages of cell cycle

Answer 49

1) DNA synthesis = replicates chromosomes for 2 copies Cell grows and copies other internal structures 2) mitosis = 1 set of chromosomes pulleys to each side of the cell. Nucleus divides 3) cytoplasm and cell membrane divide = 2 identical cells

Question 50

Mitosis functions

Answer 50

Growth and development of multicellular organisms Repair Asexual reproduction (unicellular organisms)