B1 Flashcards
1
Q
What is a differentiated cell
A
When cell becomes specialised and gains a specific function
2
Q
What’s cell division
A
Cell division- process of splitting parent cell into 2 daughter cells
3
Q
What’s cell differentiation? (2)
A
Cell acquires different subcellular structures to enable it to carry out a certain function
4
Q
What is eukaryotic cell
A
Genetic material is enclosed within nucleus
5
Q
What is prokaryotic cell
A
Genetic material not enclosed within nucleus
6
Q
Difference between eukaryotic and prokaryotic cells [3marks]
A
- where genetic info is enclosed/not
- scale- Pro are much smaller
- Pro= unicellular
Eu= multicellular
7
Q
3 features plant cell has that animal does not
A
- cell wall
- chloroplasts
- permanent vacuole
8
Q
5 main subcellular structures in animal cell
A
- nucleus
- cell membrane
- cytoplasm
- mitochondria
- ribosomes
9
Q
Define cell
A
Basic building blocks of life
10
Q
Order: organism, cell, organ, organ system, tissue
A
Cell, tissue, organ, organ system, organism
11
Q
Rank in terms of size: Chromosome, nucleus, gene, DNA
A
Nucleus, chromosome, gene, DNA
12
Q
Define secrete
A
To discharge something
13
Q
Define emulsify
A
Combine a mixture which normally doesn’t combine
14
Q
Function of nucleus
A
- controls all activities in cell
- contains genes in chromosomes which carry genetic Information
15
Q
Function of cytoplasm
A
Many chemical reactions take place
16
Q
Function of cell membrane
A
Controls substances which enter and leave cell
17
Q
Function of mitochondria
A
Where aerobic respiration takes place, releasing energy
18
Q
Function of ribosomes
A
Where protein synthesis takes place- proteins are made
19
Q
Function of chloroplasts
A
Contains chlorophyll needed for photosynthesis
20
Q
Function of cell wall
A
In plants made of cellulose, helps structure by giving strength and supporting plant cell
21
Q
Function of vacuole
A
Filled with cell sap- keeps cell rigid to support plant
22
Q
What does 1 order of magnitude mean
A
10x
23
Q
What does 3 orders of magnitude mean
A
1000x
24
Q
How do u find out magnification?
A
Magnification= size of image ÷real object
25
What is the triangle for magnification
I ÷ A x M
26
Define tissue
Group of specialised cells that work together to cary out a specific function
27
Define organ
Collection/ group of tissues that work together for a specific function
28
Define organ system
Made up of different organs working together e.g. digestive system, respiratory system
29
What is diffusion
Net movement of particles from a higher concentration to a lower concentration
30
What is osmosis
Net movement of particles from a higher concentration to a lower concentration across a partially permeable membrane
31
What is active transport
Moves substances from a more dilute solution to a more concentrated solution against a concentration gradient, requires energy from respiration.
32
Light microscope: image is formed using..., can it view live specimen, magnification, resolution, first developed
- developed mid 17th century
- image formed using light
- can view live specimen
- price- cheap
- magnification 2000x
- resolution low 200nm
33
Electron microscope: image is formed using..., can it view live specimen, magnification, resolution, first developed
- developed in 1930s
- image formed using resolution
- cant view live specimen
- price- v. Expensive
- magnification 2 000 000x
- resolution low 0.2nm
34
Factors which affect rate of diffusion
- difference in concentration (conc gradient)
- temperature
- surface area of membrane
35
1 cm into metres using standard form
1 x 10^-2 metres
1 times 10 to the power of -2
36
1 millimetre into meters
1 x 10 ^-3 metres
37
I micro meter into meters
1 x10 ^ -6 = 1 metre
38
1 nanometers into meter
1 x 10 ^ -9 meters
39
How does the concentration gradient affect the rate of diffusion
Larger the concentration gradient the higher the rate of diffusion e.g. if there's more particles to move then more diffusion will happen
40
How does temperature affect the rate of diffusion
- higher temperature gives particles more energy
- they move around faster
- diffuse more quickly
41
How does s.a. affect rate of diffusion
Larger the surface area of the membrane the faster the diffusion rate because more particles can pass through at once
42
How many chromosomes do human cells have?
Nucleus of human cell contains 23 pairs of chromosomes
43
What do chromosomes contain?
Chromosomes contain a double helix of DNA and they also have a large number of genes
44
What do bacterial cells have instead of nucleus
- single strand of dna that floats in cytoplasm
- plasmids which reproduce through binary fission
45
When can animal cells differentiate?
-Early stage
- in mature animals cell division is limited to repair and growth
46
When can plant cells differentiate
Retain ability to differentiate throughout life
47
Define magnification
How much bigger you can make an image
48
Define resolution
How much detail you can see in image
49
Describe cell cycle
- increase number of subcellular structures e.g. ribosomes, mitochondria
- duplicates DNA for 2 copies of each chromosome
-one set of chromosomes pulled by cell fibres to each end of cell+ nucleus divides
- cytoplasm+ cell membrane divide to form two identical daughter cells
50
How plant cells can be cloned from stem cells and benefits of doing this
1)take piece of specialised root
2) break them up into root cells
3) grow cells in nutrient rich culture
4) specialised cells become unspecialised
5)dedifferentiate into calluses
6) calluses can be stimulated with appropriate plant hormones to grow into new plants that are identical to original from which root pieces were taken
51
Define calluses
Growing mass of unorganised plant cells and tissues
52
Cultured meanning
Artificially grown or synthesised
53
How to find s.a:volume ratio
Surface area= length x width
Volume = length x width x height
54
Explain how surface area: volume ratio of a single celled organism (amoeba) allows sufficient molecule transport
- single celled organisms have large s.a. to volume ratio because they are so small
- able to get all oxygen n nutrients they need through diffusion through cell membrane
- short diffusion pathway
55
What is a chromosome
Long, tightly coiled molecule of DNA split into sections called genes
56
What's a gene
Section of DNA which codes for specific protein
57
What's DNA
Deoxyribonucleic acid:
- passed from parents to offspring
- controls cell activity
- contains info to specify characteristics of organism
58
What happens to plant cell placed in dilute solution
Water enters cell- becomes turgid
Cell expands and is swollen
59
What happens to plant cell placed in concentrated solution
Water leaves cell- becomes flaccid
Cell is floppy and shrinks
60
Function of muscle cell
To contract and expand quickly
61
Adaptation of muscle cell
- contains protein fibres that are able to change lengths
- packed with mitochondria to provide energy for muscle contraction
62
Function of xylem cell
Transport water and dissolved minerals through plant from roots to leaves
63
Adaptation of xylem cell
- thick walls containing lignin; provides support
- lignin makes xylem cells die- gives skeletal structure
- end walls between cells have broken down- cell now forms a long tube so 💧+ dissolved minerals can flow easily
64
Function of root hair cell
to absorb water and dissolve minerals from soil
64
Function of root hair cell
to absorb water and mineral ions from soil
65
What do root hair cells not contain
Chloroplasts- they are underground
66
Adaptation of root hair
Contains Root hair cells which increase surface area of the root so it can absorb water and dissolve minerals more effectively
67
Function of sperm cell
To penetrate the egg and get male dna to female dna
68
Adaptation of sperms cell
- streamlined head so easier to penetrate
- contains enzymes, enables it to break down outer shell of egg easily
- packed with mitochondria to provide energy needed for swimming
69
What happens during fertilisation
Genetic info of sperm and ovum fuse together/ combine
70
Function of phloem cell
Transport substances around plant
71
Adaptation of phloem cell
- phloem vessel cells have no nucleus and limited cytoplasm
- end walls of vessel cells have pores called sieve plates
- these structures allow dissolved sugars to move through cell interior
- each phloem vessel cell has compagnion cell connected by pores
- mitochondria in compagion cell provide energy to phloem cell
72
Function of nerve cell
Send electrical impulses around the body
73
Adaptation of nerve cell
- dendrites: increase s.a. so other nerve cells can connect more easily
- myelin: insulates axon + speeds up transmission of nerve impulses
- axon: carries electrical impulses from one part of body to another
- synapses: junctions which allow impulses to pass from one nerve cell to another
74
Explain adaptations of roots and leaves that help molecules diffuse efficiently across them
- each branch of root is covered in millions of root hair cells, gives plant large s.a. for absorbing water and mineral ions from soil
- flattened shape of leaf increase area of exchange surface so its more effective
- walls of cells inside leaf form another exchange surface- air spaces inside leaf increase area of surface so there is more co2 that can get into cell
75
Why is an electronic microscope better than a light microscope
- has much bigger magnification and resolution power
- can be used to study cells in much finer detail
- enabled biologists to see/understand more sub-cellular structures
76
Hypertonic
Concentrated solution
77
Hypotonic
Dilute solution
