Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Alevel Biology > 2.6 > Flashcards

2.6 Flashcards

1
Q

Cytokinesis

A

Cytoplasmic division following nuclear division resulting in 2 new daughter cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Interphase

A

Phase of cell cycle where the cell isn’t dividing, it is subdivided into growth and synthesis phases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Mitosis

A

Type of nuclear division that produces daughter cells genetically identical to each other and to the parent cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Chromatids

A

Replicates of chromosomes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Cytokinesis

A

Division of the cytoplasm of a cell following mitosis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Mitosis

A

Type of nuclear division that maintains the chromosome number, each new daughter cell contains same genetic info as parent cell,and they are genetically identical to each other

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Haploid

A

Having only one set of chromosomes represented by ‘n’ symbol

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Homologous chromosomes

A

Matching chromosomes containing the same genes at the same places (loci). They may contain different alleles for some of the genes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Meiosis

A

Type of nuclear division that results in formation of cells containing half the number of chromosomes if parent cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Haploid

A

On set of chromosomes asexual reproduction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Diploid

A

Two sets of chromosomes sexual reproduction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Gametes

A

Sex cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Zygote

A

Fusion of sperm and egg cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Allele

A

Same gene but different variant of the gene

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

How do cells reproduce

A

By dividing their contents and then splitting into 2 daughter cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What could early researchers observing cell division see under light microscope and what couldn’t they

A

Could easily see behaviour of chromosomes in mitosis which is nuclear division, followed by cytokinesis resulting in 2 daughter cells. But nuclear division and cytokinesis called M phase is only small part of of cell cycle and they couldn’t see the rest

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is between M phase

A

Interphase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What does interphase look like under a microscope

A

It appears uneventful

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

How do scientists now know interphase isn’t uneventful

A

More sophisticated techniques have enabled scientists to learn that during interphase there are elaborate preparations being made for cell division, in a carefully ordered and controlled sequence with checkpoints

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

How does cell division cycle divide up

A

M-division phase, interphase divided into G1 G2 and S and cells may also enter G0 where they undergo differentiation or apoptosis or enter senescence

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What are the 2 main checkpoints in cell cycle

A

G1/S checkpoint aka restriction checkpoint and G2/M checkpoint

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What other less important checkpoints are there in cell cycle

A

One half way through mitosis and in early G1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What is the role of checkpoints

A

To prevent uncontrolled cell division that would lead to tumours/cancer and to detect and repair damage to DNA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

The molecular events that control cell cycle happen in specific sequence so why are checkpoints also important

A

So cycle can’t be reversed and so DNA only replicated once during each cycle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What is the purpose of the cell cycle

A

For growth and repair, asexual reproduction and to replace old cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

How does cancer occur in terms of cell cycle

A

Cells divide uncontrollably, mitosis takes same length of time in cancerous cells but division is uncontrolled so their is a higher proportion of cells dividing in a tissue. Interphase is shorter in proto-oncogens which regulate cell division and growth, proto-oncogens are muted so they don’t undergo cell death as they normally should

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What is M phase and what checkpoints are involved

A

A checkpoint chemical triggers condensation of chromatin. Halfway through cycle, metaphase checkpoint ensures that cell is ready to complete mitosis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What happens to cell in M phase

A

Cell growth stops, nuclear division(mitosis) occurs, followed by cytokinesis/cytoplasmic division

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

What is G0 phase and what checkpoints involved

A

It’s the resting phase triggered during early G1, at restriction checkpoint by a checkpoint chemical. Some cells like epithelial cells lining gut don’t have this phase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

What happens to the cell in G0 phase

A

Cells may undergo apoptosis (programmed cell death), they may undergo differentiation or senescence(no longer divide), some types of cells like neurones remain in this phase for a long time/indefinitely

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

What is G1 phase and what checkpoints involved

A

Also called growth phase, a G1 checkpoint controls mechanism and ensures cell is ready to enter S phase and begin DNA synthesis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

What happens to cell at G1 phase

A

Cells grow and increase size(organelles duplicate), transcription of genes to make new RNA occurs, biosynthesis occurs (creates enzymes needed for DNA replication) and p53 tumour suppressor gene helps control this phase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

What is S phase and what checkpoints involved

A

Chromosomes unwind and every molecule of DNA is replicated. There’s a specific sequence to the replication of genes: housekeeping genes (those which are active in all cell types) are duplicated first. Genes that are normally inactive in specific cell types are replicated last

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

What happens to the cell in S phase

A

It’s vomited to completing cell cycle in this phase, DNA replicates, when all chromosomes duplicated each one has an identical sister chromatid, phase is rapid as due to exposed DNA base pairs being susceptible to mutagenic agents, it reduces changes of spontaneous mutations happening

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

What is G2 phase and what checkpoints are involved

A

Special chemicals ensure cell is ready for mitosis by stimulating proteins that will be involved in making chromosomes condense and in formation of the spindle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

What happens to cell in G2 phase

A

Cell grows

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

Why do all living organisms need to produce genetically identical daughter cells by mitosis

A

Asexual reproduction, growth and tissue repair

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

What is asexual reproduction

A

Single felled protoctists like amoeba and paramecium divide by mitosis to produce new individuals, some plants like strawberries reproduce asexually by forming new plantlets on end of stolons (runners) and fungi like single cells yeast reproduce asexually by mitosis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

Is asexual reproduction rate or common in animals give 2 example

A

Rater in animals than plants but some female sharks in captivity with no male produce genetically identical daughter sharks and aphids may produce eggs by mitosis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

How does mitosis help with growth

A

All multicellular organisms grow by producing more cells that are genetically identical to each other and their parent cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

How does tissue repair done by mitosis

A

Wounds heal when growth factors, secreted by platelets and macrophages and damaged cells of blood vessel walls simulate proliferation of endothelial and smooth muscle cells to repair damaged blood vessel

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

Is mitosis continuous process and what are the 4 main stages

A

It is a continuous process and 4 stages are prophase, metaphase, anaphase, telophase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

What are the events during early prophase

A

Chromosomes that replicated during S phase and consist of 2 identical sister chromatids now shorten and thicken as DNA supercoils, and nuclear envelope breaks down

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

What are the events in late prophase

A

Centriole in animal cells (found in region of cell called centrosome) divide and 2 new daughter centrioles move to opposite poles of the cell. Cytoskeleton protein tubulin threads form a spindle between these centrioles, spindle had 3D structure, similar to longitude lines on globe. In plant cells, tubulin cells formed from cytoplasm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

What are the events during metaphase

A

Pairs of chromatids attach to spindle threads at equator region, they attach by their centromeres

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

What are the events during anaphase

A

Centromere of each pair of chromatids split, motor proteins walking along tublin threads pulls each sister chromatid of a pair in opposite directions to opposite poles. As their centromere goes first, the chromatids now called chromosomes assume V shape

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

What are the events during telophase

A

Separate chromosomes reach the poles, new nuclear envelope forms round each set of chromosomes. Cell now contains 2 nuclei each genetically identical to each other

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

What happens once mitosis is complete

A

Cells split into 2 so each new cell contains a nucleus-cytokinesis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
49
Q

How does cytokinesis work in animal cells

A

Plasma membrane folds inwards and ‘nips in’ the cytoplasm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
50
Q

How does cytokinesis work in plant cells

A

An end plate forms where the equator of spindle was and new plasma membrane and cellulose cell wall material are laid down on either side along this end plate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
51
Q

What happens after cytokinesis

A

2 new daughter cells are now formed, they are genetically identical to each other and to parent cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
52
Q

What does sexual reproduction increase

A

Genetic variation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
53
Q

How does sexual reproduction increase genetic variation

A

It involved combining of genetic material from 2 unrelated individuals of same species by process of fertilisation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
54
Q

What does genetic variation within a population increase

A

Chances of survival when environment changes as some individuals will have characteristics that enable them to better adapt to the changes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
55
Q

What must body cells be in many organisms for meiosis to occur

A

Body cells are diploid and they must be haploid gametes for sexual reproduction to occur, so when 2 gamete nuclei fuse during fertilisation, a diploid zygote is produced and Norma chromosome number is maintained through the generations

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
56
Q

What does meiosis mean and when does it occur

A

Means reduction and it occur in diploid germ cells to produce haploid gametes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
57
Q

Where are diploid cells undergoing meiosis found

A

In specialised organs called gonads-ovaries and testes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
58
Q

What happens before meiosis

A

Cells are in interphase before meiosis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
59
Q

How many chromosomes in human body

A

46chromosomes, 23 from mum (egg nucleus), 23 from dad (sperm nucleus)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
60
Q

What are homologous chromosomes

A

1 maternal and 1 paternal chromosome containing same genes at same places on a chromosome, these matching pairs are homologous chromosomes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
61
Q

Even though homologous chromosomes have same genes what may be different about them

A

They may contain different alleles of the gene

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
62
Q

What happens before meiosis in S phase of interphase

A

Each chromosome is duplicated as its DNA is replicated l, after which each chromosome consists of 2 sister chromatids (chromosomes pair up in homologous pairs).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
63
Q

How many divisions are in meiosis and how many stages in each division

A

2 divisions, 4stages in each

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
64
Q

What are the stages of meiosis

A

Prophase 1, metaphase 1, anaphase 1, telophase 1, prophase 2, metaphase 2, anaphase 2, telophase 2, cells may enter short interphase before prophase 2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
65
Q

Where does the 2nd stage of meiosis take place

A

At eighth angle to meiosis 1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
66
Q

What happens after 2nd division in meiosis

A

Cytokinesis occurs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
67
Q

What are the events during prophase 1 in meiosis

A

Chromosomes condense and each one supercoils, nuclear envelope breaks down and spindle threads from tubulin protein form from centrioles, chromosomes come together in their homologous pairs, each member of pair consists of 2 chromatids, crossing over may occur

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
68
Q

What is crossing over in meiosis

A

Where non-sister chromatids wrap round each tiger and may swap sections so alleles are shuffled, which creates genetic variation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
69
Q

What are events in metaphase 1 in meiosis

A

Pairs of homologous chromosomes still in crossed over state, attach along equator of spindle. Each attached to spindle thread by its centromere. Homologous pairs arranged randomly with members of each pair facing opposite poles(independent assortment), way they are lined up in metaphase determines how they will segregate independently when pulled apart in anaphase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
70
Q

What happens in anaphase 1 in meiosis

A

Members of each pair of homologous chromosomes are pulled apart by motor proteins that drag them along tubulin thread of spindle. Centromeres don’t divide and each chromosome had 2 chromatids, crossed over areas separate from each other resulting in swapped areas of chromosomes and allele shuffling

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
71
Q

What are events during telophase 1 in meiosis

A

In most animal cells 2 new nuclear envelopes form around each set of chromosomes and cell divides by cytokinesis, there is then short interphase when chromosomes uncoil. Each new nucleus contains half original number of chromosomes but each chromosome has 2 chromatids. In plant cells, cell goes straight from anaphase 1 to prophase 2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
72
Q

What happens in prophase 2 in meiosis

A

If nuclear envelopes reform then they break down, chromosomes coil and condense, each one consisting of 2 chromatids, chromatids of each chromosomes are no longer identical due to crossing over in prophase 1. Spindle forms

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
73
Q

What are events in anaphase 2 in meiosis

A

Centromeres divide, chromatids of each chromosome are pulled apart by motor proteins that drag them along the tubulin threads of spindle, towards opposite poles, chromatids are therefore randomly segregated

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
74
Q

What happens during metaphase 2 in meiosis

A

Chromosomes attach by their centromere to equator of spindle, chromatids of each chromosome are randomly arranged, the way that they are arranged will determine how chromosomes are separated during anaphase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
75
Q

What happens during telophase 2 in meiosis

A

Nuclear envelopes form around each of the 4 haploid nuclei, in animals the 2 cells now divide to give 4 haploid cells. In plants, a tetrad of 4 haploid cells is formed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
76
Q

What does crossing over do in meiosis and what stage does it happen

A

Shuffles alleles and occurs in prophase 1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
77
Q

What does independent assortment of chromosomes in anaphase 1 led to

A

Random distribution of maternal and paternal chromosomes of each pair

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
78
Q

What does independent assortment of chromatids in anaphase 2 lead to

A

Further random distribution of genetic material

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
79
Q

What happens after meiosis

A

Haploid gametes are produced which can undergo random fusion with gametes derived from another organism of same species

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
80
Q

In single celled organisms like amoeba how is division of labour determined

A

By organelles each with specific functions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
81
Q

What does single cell organisms being small mean

A

Large SA:V ratio so O2 can diffuse across their plasma membrane and waste diffuses out through same membrane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
82
Q

What does multi cellar organisms having small SA:V ratio mean

A

Most of their cells aren’t in contact with external environment so need specialised cells to carry out their function

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
83
Q

How do multicellular eukaryotic organisms start life

A

As a single undifferentiated cell called a zygote

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
84
Q

When does a zygote result

A

When ovum(egg cell) is fertilised by spermatozoon and 2 haploid nuclei fuse to give a cell with diploid nucleus

85
Q

Is zygote specialised and what does this mean

A

Zygote isn’t specialised and all the genes in its genome are able to be expressed (also able to divide by mitosis)

86
Q

What is a zygote

A

A stem cell

87
Q

What happens to zygote after several meiotic divisions

A

An embryo form containing many undifferentiated embryonic cells

88
Q

Why do embryonic cells differentiate as certain genes switched off and others expressed more

A

So that proportions of different organelles differ from those of other cells, shape of cell changes, some contents of cell change

89
Q

After differentiate what is every cell

A

Specialised for particular function

90
Q

In mammals what is an erythrocyte function

A

Carey oxygen from lungs to respiring cells

91
Q

In mammals what are neutrophils function

A

To ingest invading pathogens

92
Q

How are erythrocytes and neutrophils similar

A

Very different but both derive from the stem cells in bone marrow

93
Q

How are erythrocytes adapted to carry out their function

A

They are small so have large SA:V so oxygen can diffuse across their membrane and reach all regions of cell inside (biconcave shape increases SA:V ratio). They are flexible and have well developed cytoskeleton which allows them to change shape to twist and turn through narrow capillaries, most of organelles lost at differentiation so have no nucleus, mitochondria, ER and little cytoplasm providing space for haemoglobin molecules

94
Q

How is haemoglobin synthesised

A

In immature erythrocytes whilst they still have their nucleus, ribosomes and RER

95
Q

How are neutrophils adapted to their function

A

They make up 50% of WBC in body, twice the size of erythrocytes and each neutrophil has multi lobed nucleus. They are attracted to and travel towards infection sites by chemotaxis. Their function is to ingest bacteria and fungi by phagocytosis

96
Q

How are spermatozoa specialised

A

Many mitochondria to carry out aerobic respiration, ATP provides energy for undulipodium to move cell towards the ovum. Spermatozoa can easily move as they are small, long and thin. Once it reaches ovum enzymes are released from acrosome (specialised lysosomes) and enzymes digest outer protective cover of ovum so sperm head can enter ovum. Head of sperm has a haploid male gametes nucleus and little cytoplasm

97
Q

How are epithelial cells adapted to their function

A

Epithelium is lining tissue, found on out and inside of body like alveoli walls and capillaries and lining intestines. Squamous epithelial cells have flattened shape and many epithelial cells have cilia

98
Q

What are acrosomes

A

Specialised lysosomes

99
Q

What is order of plant leaf from cuticle to stomata

A

Cuticle, upper epidermis, palisade layer, xylem and phloem, spongy mesophyll, lower endodermis, guard cell, stomata

100
Q

What is lay out of guard cell

A

Have thickened inner wall, stomata in the middle and chloroplast in the guard cell

101
Q

Why are palisade cells within leaves well adapted for photosynthesis

A

They’re long and cylindrical cells, so they pack together closely but with a little space for air to circulate between them and CO2 in these air spaces diffuse into cells, have large vacuole so chloroplasts positioned nearer to periphery of cell which reduces diffusion distance of CO2, they also contain many chloroplasts and contain cytoskeleton threads and motor proteins to move chloroplasts nearer to upper surface of leaf when sun intensity is low and further down when it’s high

102
Q

Do guard cells contain chloroplasts

A

Yes

103
Q

Even through guard cells have chloroplasts why can’t they carry out photosynthesis

A

They don’t have enzyme needed for 2nd stage of photosynthesis

104
Q

How are guard cells adapted

A

Light energy used to make ATP, the ATP actively transports potassium ions from surrounding epidermal cells into guard cells lowering their water potential, water now enters guards cells by osmosis so guard cells swell but at tips cellulose cell wall is more flexible and more rigid when it’s thicker, tips bulge and gaps form between them, stomata enlarged

105
Q

What happens as stomata open

A

Sit can enter spaces in layer of cells beneath palisade cells, gaseous exchange occurs and CO2 diffuses to palisade cells as they use it for photosynthesis (maintains steep concentration gradient). Oxygen produced during photosynthesis can diffuse out of palisade cells into air spaces and out through open stomata, when stomata open water vapour lost

106
Q

What are root hair cells

A

Epidermal cells on outer layer of young plant roots

107
Q

How are root hair cells adapted to their function

A

Hair like projections increase SA for absorption of water and mineral ions, like nitrates, from soil which it projects, mineral ions actively pumped into root hair cell so water potential lowers and water moves in by osmosis down water potential gradient, root hair cells have special carrier proteins in plasma membrane to actively transport mineral in and these cells also produce ATP needed for active transport

108
Q

What are xylem and phloem

A

Form vascular tissue of a plant, xylem vessel and phloem sieve tubes are present in vascular bundle

109
Q

What are cells

A

Basic building blocks of living organisms

110
Q

What happens to cells in multicellular organisms and why

A

Cells become specialised for different functions

111
Q

What is a tissue

A

A group of similar cells working together to perform a certain function

112
Q

What are the human body 4 main types of tissue

A

Epithelial/lung tissue, connective tissue, muscle tissue, nervous tissue

113
Q

What is connective tissue

A

Hold structures together and provide support like blood, bone, cartilage

114
Q

What is muscle tissue

A

Made of cells that are specialised to contract and cause movement

115
Q

What is nervous tissue

A

Made of cells specialised to conduct electrical impulses

116
Q

What does epithelial tissue do

A

Covers and lines free surfaces like skin, cavities of digestive and respiratory system, blood vessels, heart chambers, walls of organs

117
Q

What are some characteristics of epithelial tissue

A

Made up almost entirely of cells, each cell is close to each other and form continuous sheet (adjacent cells bound together by lateral contacts like tight junctions and desmosomes),
no blood vessels in epithelial tissue-cells receive nutrients by diffusion from tissue fluid in underlying connective tissue, epithelial tissue either has smooth surface or projections like vili and cilia, have a short cell cycle to constantly replace damaged tissue,

118
Q

What is epithelial specialised to carry out

A

It’s function of protection, absorption, filtration, excretion and secretion

119
Q

Where is connective tissue found in the body

A

Widely distributed around the body

120
Q

What does connective tissue consist of

A

Non-living extracellular matrix containing proteins(collagen and elastin) and polysaccharides like (hyaluronic acid, which traps water)

121
Q

What is connective tissues function

A

Separates living cells within tissue and enables it to withstand forces like weight

122
Q

What are examples of connective tissue (6)

A

Blood, bone, cartilage, tendons, skin and ligaments

123
Q

What are immature cells in cartilage called

A

Chondroblasts

124
Q

What can chondroblasts do

A

Divide by mitosis and secrete the extracellular matrix

125
Q

What happens to chondroblasts once matrix has been synthesised

A

They become mature and less active chondrocytes maintain the matrix

126
Q

What are the 3 types of cartilage

A

Hayline, fibrous, elastic

127
Q

Where is hayline cartilage found

A

Forms embryonic skeleton, covers ends of long bones in adults, joins ribs to sternum, found in nose and in the trachea (c-shaped rings keeping it open) and in larynx(voice box)

128
Q

Where is fibrous cartilage found

A

In discs between vertebrae in backbone and in knee joints

129
Q

Where is elastic cartilage found

A

Makes up outer layer of ear (pinna) and the epiglottis (flap that closes larynx when you swallow

130
Q

How is muscle tissue specialised

A

Well vascularised( many blood cells), muscle cells called fibres as they are elongated and contain special organelles called microfilaments made of protein actin and myosin which allow muscle tissue to contract

131
Q

What is the function of muscle tissue

A

To allow movement

132
Q

What are the 3 types of muscle tissue

A

Skeletal muscle, cardiac muscle, smooth muscle

133
Q

What is skeletal muscle

A

Packaged by connective tissue sheets, joined to bones by tendons, they cause bone to move when contracted

134
Q

What is the cardiac muscle

A

Makes up walls of heart and allows heart to beat and pump blood

135
Q

What is smooth muscle

A

Occurs in walls of intestines, blood vessels, uterus and urinary tract and it propels substances along these tracks

136
Q

What are the 3 main types of plant tissue

A

Epidermal, vascular, meristematic tissue

137
Q

What is epidermal tissue

A

Equivalent to epithelial tissue in animals, consisting of flattened cells that (apart from guard cells) lack chloroplast and form a protective covering over outer leaves, stems and roots

138
Q

What do some epidermal cells also have

A

Walls impregnated with waxy substance forming cuticle, particularly important to plants that live in dry places as it reduces water loss

139
Q

What is vascular tissue

A

Concerned with transport-xylem and phloem, both in vascular bundle

140
Q

What are function of xylem and then phloem

A

Xylem vessel carry water and minerals from roots all parts of the plant, phloem sieve tubes transfer products of photosynthesis (sucrose) in solution from leaves to parts of the plant the don’t photosynthesis like roots, flowers and growing shoots

141
Q

What is meristematic tissue

A

Contains stem cells, from this tissue that all other plant tissues are derived from by cell differentiation

142
Q

Where is meristematic tissue found

A

At roots and shoot tips and in cambium of vascular bundle

143
Q

What are special features of cells in meristematic tissue (meristems)

A

Have thin walls and little cellulose, don’t have chloroplasts, don’t have large vacuoles, can divide by mitosis and differentiate into other types of cells

144
Q

What is an example of meristematic tissue

A

Onion root tips are which is why many of their cells are dividing when viewed under a microscope (mitosis PAG)

145
Q

What happens as most plant cells mature

A

They develop a large vacuole and rigid cellulose cell wall which prevents cell from dividing (but plants need to grow and produce new cells, new cells arise at meristems by mitosis)

146
Q

What do some cambium cells differentiate into

A

Xylem vessels

147
Q

What happens to xylem vessel as it mature

A

Lignin is deposited in their cell walls to reinforce and waterproof them but also kills cells, ends of cell break down so xylem is a continuous column with wide lumen to carry water and dissolved minerals

148
Q

What do other cambium cells differentiate into

A

Phloem sieve tubes or companion cells

149
Q

What happens as sieve tubes and companion cells mature

A

Sieve tubes lose most of their organelles and sieve plates develop between each cell, companion cells retain their organelles and continue metabolic functions to produce ATP for active loading of sucrose into sieve tubes

150
Q

What is an organ

A

Collection of tissues working together to perform same function

151
Q

What is the organ (leaf) function in a plant

A

The photosynthesis

152
Q

What is the organ (root) function in a plant

A

Anchorage in soil, absorption of mineral ions and water, storage of carbohydrates

153
Q

What is the organ (stem) function in a plant

A

Support, holds leaves up so exposed to more sunlight, transport of water and minerals, transport of photosynthesis products, storage of photosynthesis products

154
Q

What is the organ (flower) function in a plant

A

Sexual reproduction by meiosis

155
Q

What are examples of organs in animals (8)

A

Heart, kidney, liver, brain, optic nerve, bicep muscle, lungs and eyes

156
Q

What is an organ system

A

A number of organs working together to carry out overall function of life

157
Q

What organs/tissues are involved in the organ system (digestive system)

A

Oesophagus, stomach, intestines and associated glands, liver and pancreas

158
Q

What life process is carried out by the organ system (the digestive system)

A

Nutrition to provide ATP and materials for growth and repair

159
Q

What tissues/organs involved in the organ system (circulatory system)

A

Heart and blood vessels

160
Q

What is the life process carried out by the organ system (circulatory system)

A

Transport to and from cells

161
Q

What is organ/tissue involved in the organ system (respiratory system)

A

Airways and lungs, diaphragm and intercostal muscles

162
Q

What is the life process carried out by organ system (respiratory system)

A

Breathing and gaseous exchange excretion

163
Q

What organs/tissues involved in organ system (urinary system)

A

Kidneys, ureters and bladder

164
Q

What life process is carried out by organ system (urinary system)

A

Excretion and osmoregulation

165
Q

What organs/tissues are involved in integumentary system

A

Skin, hair and nails

166
Q

What life process is carried out by the organ system (integumentary system)

A

Waterproofing, protection and temp regulation

167
Q

What are organs/tissues involved in organ system, musculoskeletal system

A

Skeleton and skeletal muscles

168
Q

What is the life process carried out by the organ system musculoskeletal system

A

Support, protection and movement

169
Q

What is the organs/tissues involved in the immune system

A

Bone marrow, thymus gland, skin, stomach acid and blood

170
Q

What is the life process carried out by the organ system (immune system)

A

Protection against pathogens

171
Q

What is the tissues/organs involved in the organ system (nervous system)

A

Brain, spinal chord and nerves

172
Q

What is life process carried out by nervous system

A

Communication, control and coordination

173
Q

What organs/tissues involved in endocrine system

A

Glands that make hormones like thyroid, ovaries, testes and adrenals

174
Q

What is life process carried out by organ system endocrine system

A

Communication, control and coordination

175
Q

What organs/tissues involved in reproductive system

A

Testes, penis, ovaries, uterus and vagina

176
Q

What life process is carried out by organ system, reproduction system

A

Reproduction

177
Q

What organs/tissues involved in lymph system

A

Lymph nodes and vessels

178
Q

What life process is carried out by organ system, lymph system

A

Transports fluid back to the circulatory system and is also important in resisting infections

179
Q

What are stem cells

A

Undifferentiated cells capable of becoming any cell in the organism

180
Q

What are stem cells described as and why

A

Pluripotent as they can differentiate into many cell types

181
Q

What can stem cells do which others can’t

A

Express all their genes, can divide by mitosis and provide more cells that can then differentiate into specialised cells for growth and tissue repair

182
Q

What do stem cells characteristics make them important for

A

Medical research and use

183
Q

What sources are different stem cells obtained from

A

Embryonic stem cells, am Oli also chord blood stem cells, adult stem cells, induced pluripotent stem cells

184
Q

What are embryonic stem cells

A

Present in early embryo formed when zygote begins to divide

185
Q

Where are stem cells found in umbilical chord

A

In umbilical chord blood

186
Q

What are adult stem cells

A

Also in kids, are found in developed tissue like blood, brain, muscle, bone, adipose tissue and skin, amounts differentiate cells

187
Q

What are adult stem cells function

A

They act as repair system as they are renewing source of undifferentiated cells

188
Q

What are induced pluripotent stem cells (iPS cells)

A

They are developed in labs by reprogramming differentiated cells to switch on certain key genes and become undifferentiated

189
Q

What are stem cells from bone marrow used to treat

A

Used in bone marrow transplant to treat disease of the blood

190
Q

What are some blood diseases which can be treated by bone marrow transplant

A

Sickle-cell anaemia and leukaemia and immune system diseases like severe combined immunodeficiency or SCID

191
Q

Apart from treating blood diseases what can bone marrow stem cells be used to treat

A

Can restore patients blood system after treatment for specific cancer types, where patients bone marrow cells can be obtained before treatment, stored and then put back inside patient after treatment

192
Q

How has stem cells changed drug research

A

If stem cells can be made to develop into particular types of human tissue, then new drugs can be tested first on these tissues rather than on animal tissue

193
Q

What are some ways scientists make use of stem cells

A

To research developmental biology and enable better understanding of how multicellular organisms develop, grow and mature

194
Q

Why have scientists starting using stem cells to study how stem cells develop

A

To make certain cell types (blood,bone,muscle,skin) and can learn how each cell type functions and see what hat goes wrong if they’re diseased

195
Q

What are scientists trying to find out about stem cells

A

If they can extend capacity that embryos have for growth and tissue repair into later life

196
Q

Why is stem cell research ongoing

A

As it’s difficult to culture stem cells in a lab

197
Q

Why is it hard to culture stem cells in a lab

A

It’s necessary to find out which cytokine cell signalling molecules are needed to direct the differentiation of stem cells into particular cell types

198
Q

How have stem cells been used in diabetes treatment

A

Used to treat mice with type 1 diabetes by programming iPS cells to become pancreatic beta cells and research is underway to develop this treatment in humans for type 1 diabetes

199
Q

How have stem cells been used to treat liver disease

A

Bone marrow stem cells can be made to develop into liver cells (hepatocytes) and treat liver disease

200
Q

How could stem cells treat Alzheimer’s, Parkinson’s or repair spinal chord injuries

A

Stem cells could be directed to become nerve tissue which could treat these diseases

201
Q

What is regenerative medicine

A

Stem cells may be used to populate a bioscaffold of an organ and then directed to develop and grow specific organs for transplanting

202
Q

How can regenerative medicine mean there is no need for immunosuppressant drugs

A

If patient cells are obtained and reprogrammed to become iPS cells and used to make a specific organ there will be no need for immunosuppressant drugs

203
Q

What other conditions may stem cells eventually be able to treat

A

Arthritis, strokes, burns, vision, hearing loss, duchenne muscular dystrophy and heart disease

204
Q

Difference between pluripotent and multipotent

A

Pluripotent can for whole tissue types but not living organisms, multipotent can only form a range of cell types

205
Q

What is totipotent

A

Cells can differentiate into any type of cell and produce a whole organism like a zygote (only fertilised egg and first few cells made by early cell division are totipotent)

206
Q

What are the 3 types of stem cells and where are each found

A

Totipotent-in fertilised egg,zygote pluripotent-embryo multipotent-adult stem cells, bone marrow

207
Q

Why does bone marrow need stem cells

A

Red blood cells don’t have a nucleus so can’t divide by mitosis and therefore need to generate new cells once their cell cycle is finished. Also neutrophils have a limited cell cycle and need bone marrow stem cells to replace them

208
Q

Where are adult stem cells found

A

Brain, liver, skin, bone marrow

Alevel Biology (25 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions