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Biology B > Topic 2 Done > Flashcards

Topic 2 Done Flashcards

1
Q

Light vs electron microscope

A

Light has lower magnification and resolution
Electron is better for dead things and have very small wavelength

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2
Q

Two types of electron micrographs

A

Transmission electron micrographs are 2D
Scanning electron micrographs are 3D but have a lower magnification

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3
Q

What does a simple phospholipid bilayer allow through with nothing else

A

Only some fat soluble organic molecules

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4
Q

What determines how freely the proteins float in a membrane (fluid mosaic model)

A

More unsaturated fats mean membrane is more fluid

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5
Q

What is a gated channel

A

When a channel formed by a protein can be open or shut depending on cell conditions

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6
Q

What is a vesicle

A

A membrane bag that holds secretions made in cells

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7
Q

What is the protoplasm

A

Everything inside cell membrane

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8
Q

What is chromatin

A

mixture of DNA and proteins that form the chromosomes

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9
Q

What is nucleolus

A

Extra dense area of nucleus with only DNA and protein

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10
Q

Mitochondria structure and function

A

Site of respiration. Has an inner and outer membrane. Inner is folded to form cristae to give it a large SA. This has a fluid matrix inside.

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11
Q

What is the endosymbiotic theory of evolution of eukaryotic cells

A

Some cell organelles have their own DNA and over years have become part of a cell but were alone before

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12
Q

What is a centriole

A

A bundle of tubules which are used in cell division. They form the spindle fibres

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13
Q

What is the cytoskeleton and its function

A

A feature of all eukaryotic cells. A dynamic, structure that fills the cytoplasm made up of microfilaments and microtubules.
Keeps things in place, cell movement and transport in cells

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14
Q

What are cytoskeleton tubules mainly made of

A

Globular protein tubulin

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15
Q

What is a vacuole in an animal cell and what is a specific type

A

A contractile vacuole is important as they allow water content. Never permanent but can form.

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16
Q

What is endoplasmic reticulum as a whole

A

A network spread through the cytoplasm.
the site of synthesis for many chemicals

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17
Q

80s vs 70s ribosomes

A

Both can be present in eukaryotic cells. 70s are found in the mitochondria and chloroplasts so evidence they were independent. Have different rations of RNA to protein
70s are also found in prokaryotes with same job

80s is 60+40
70s is 50+30

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18
Q

What is the rough ER

A

Covered in 80s ribosomes. Makes proteins and then isolates + transports them. Has a very large SA.

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19
Q

What is the smooth ER

A

Involved in synthesis and transport of steroids and lipids

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20
Q

What does it look like and what is the Golgi apparatus

A

Made up of stacks of cisternae, formed by vesicles from endoplasmic reticulum fusing together.
Modifies and packages proteins pinched from RER

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21
Q

What is a lysosome and what does it look like

A

Dark, spherical bodies in the cytoplasm containing a mix of digestive enzymes

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22
Q

What is the process of lysosome destructiomn

A

Apoptosis. Lysosome ruptures to release cell content

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23
Q

Describe the plant cell wall and what it does, is made up of,

A

Gives the plant structure. made of insoluble cellulose. Is not a barrier for things getting in/out. Has middle lamella made of pectin, which combines with calcium ions to form strong calcium pectate which binds with cellulose to form cellulose microfibrils. Hemicellulose hardens it more.

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24
Q

How does the cell wall change

A

Can be inpregnated with Suberin in cork or lignin to make wood. Becomes a barrier

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25
What is the plasmodesmata and what is the interconnected cytoplasm called
A cytoplasmic bridge that allows communication and transport of substances between cells. Symplast exists between cells.
26
What is the Permanent Vacuole in plants
In non woody plant cells it is a permanent structure surrounded by the tonoplast membrane. Filled with CELL SAP which brings water in by osmosis. Keeps the cell turgid. Used for storage of proteins, pigments, waste products
27
Describe choloplasts
Site of photosynthesis. Have outer membrane, inner membrane that is folded. Contain chlorophyll.
28
What is an amyloplast
Colorless organelle that stores starch
29
What is the order of organisation of cells
Cells - tissues - organs - organ systems
30
How many main tissue types are there in the body and name them
Four. Epithelial, connective, muscle and nervous
31
Difference between eukaryotic and prokaryotic cells
EUKARYOTES HAVE NUCLEUS
32
Describe the bacterial cell wall and its job
Cell wall prevents cell swelling due to lower water potential inside. has peptidoglycan layer. Maintains shape and protection.
33
What is the capsule of a bacteria
A thin layer that protects the bacteria against phagocytosis. Covers the cell markers that are used to identify it.
34
What are pilli and major disadvantage
Thread like protein projections that are used for movement, attatchment to host and sexual reproduction. Make bacteria succeptible to bacteriophage.
35
What are flagellum
Tail like and is used for movement
36
Differences between cell membrane in prokaryote and eukaryote
Cell membrane is site of respiratory enzymes because of no mitochondria. Some bacterial cells have infolds called mesosomes.
37
what is a mesosome
infold in bacertia wall with debated function.
38
Describe the DNA of a prokaryotic cell
Small circles of DNA called plasmids only code for specific part and can reproduce independently. Nucleoid contains the single length of DNA.
39
2 Types of bacteria: differences
Gram positive has one plasma membrane, thick outer peptidoglycan layer with teichoic acid and surface proteins Gram negative has two plasma membranes and thin peptidoglycan layer. Has lipopolysaccharides and outer membrane proteins
40
Different types of bacteria by shape ( 4 types ) how to spot
Cocci - Spherical Baccili - rod shapes Spirilla - Twisted Vibrios - Comma shaped
41
How to class bacteria by respiratory requirements
Obligate aerobes need oxygen Facultative anaerobes only use when available Obligate anaerobic can only respire without oxygen
42
What is a virus (most scientists define)
obligate intracellular parasite that only exists and reproduces in the cells of other living organisms
43
Describe the viral protein coat
A capsid made of simple repeating protein units called capsomeres.
44
How to classify viruses by their genome and mode of replication.
DNA Virus RNA Virus RNA Retrovirus
45
What is a DNA virus and examples
Virus with DNA as genetic material used directly as a template for new viral DNA and mRNA used to synthesise proteins. Smallpox, adenovirus and lambda phage
46
What is a RNA virus, the two types and examples
Positive ssRNA virus have RNA that acts as mRNA and is immediately translated by the ribosomes. Tobacco mosaic, polio Negative ssRNA has RNA that isn't directly translated so much be transcribed first. Measles, influenza, ebola
47
What is an RNA retrovirus and give examples.
Special type with protein capsid. Reverse transcriptase is used to make DNA molecules which is then incorporated into the host cell DNA and used as template. HIV
48
Use of lipid envelope for viruses
makes it easier for viruses to pass from cell to cell
49
How do plant viruses commonly get into the plant cell
A vector such as an insect
50
What are the 2 DNA virus replication pathways. State
Lysogenic and lytic.
51
Describe the lysogenic pathway
Many DNA viruses are non-virulent when they first get into the host cell. They insert their DNA into the host DNA so it is replicated every time the host cell divides. This DNA inserted into the host is called a provirus. Messenger RNA is not produced from the viral DNA because one of the viral genes causes the production of a repressor protein that makes it impossible to translate the rest of the viral genetic material. The virus does not affect the host cell or make the host organism ill at this stage in the life cycle. During this period of lysogeny, when the virus is part of the reproducing host cells, the virus is said to be latent
52
Lytic Pathway
Genetic material is replicated independent of host DNA immediately. Mature viruses are assembled and host cell will burt. The virus is virulent. Lysogenic state viruses are activated in certain ways
53
RNA retrovirus replication process
Viral particles leave cell by exocytosis so host remains are a virus producing cell.
54
How do antiviral drugs work
Cannot target virus particles themselves. 1. Target enzymes that help translate virus DNA or RNA 2. Target receptors viruses use to recognise cells 3. Inhibit production of new virus particles
55
Stages of mitosis and what happens in each
Interphase - Cell increases in mass and size. DNA is replicated Prophase - Chromosomes coil up, centrioles begin to move to opposite poles and form spindle fibres. Nucleus breaks down Metaphase - Chromatids line up along the equator of the cell and spindle fibres attach Anaphase - Spindle fibres contract and sister chromatids are pulled towards opposite poles Telophase - Spindle fibres break down, nucleoli and centrioles reform. Chromosones unravel Cytokinesis - Contractile ring tightens until cell divides in animal cell, in plant cell cellulose just builds up
56
What do histones do and what do they help form
Pack DNA closely together in clusters known as nucleosomes
57
Phases of interphase
G1 - Gap is when cell is assimilating material, growing and developing. S - is when chromosomes replicate to become double stranded chromatids G2 - time that organelles needed for cell division are synthesised
58
How is cell division controlled
Small proteins called cyclins. Build up and attached to, cyclin depended kinases CDK's which brings about the next step in the cell cycle through phosphorylation
59
Different strategies of asexual reproduction
Producing spore - sporulation involving production of asexual spores that are capable of growing into new individuals. Regeneration - When organisms replace lost body parts. Fragmentation - Organsims reproducing themselves asexuals from fragments of their original body. Producing buds - Budding is when a small new individual forms as part of parent organism Vegetative propagation - Like budding but with runners, containing stored food and are very resistant.
60
Differences between mitosis and meiosis
The two chromosomes of each pair stay close together and crossing over occurs (prophase 1). Centromeres do not split in first meiosis so cell goes straight to mitosis 2.
61
How does meiosis produce variation
Independent assortment - Different combinations in the assortment of the chromosomes as they line up along the centre means that some will be taken from mother some from father every time in different ratio Crossing over - Similar sections of genetic material is exchanged between chromosomes forming new mutations
62
Where does crossing over occur
At the chiasma, usually far from centromere
63
Gametogenesis in animals
Spermatogenesis - Primordial germ cell divides by mitosis to form spermatogonia Spermatogonia grow until they are spermatocytes spermatocytes divide by meiosis to form spermatids spermatids then differentiate to form spermatozoa Oogenesis - Primordial germ cell divides by mitosis to form oogonia One oogonia becomes the primary oocyte oocyte does meiosis. only does second division after fertilisation
64
What is ebola: symoptoms, spread, how to treat
fever, headache, jopint and muscle pain, vomiting virus and spreads through faeces, urine, blood and meat of infected animals. also person to person through contact high mortality rate rapid identify nursing in isolation sterilise equipment identifying contacts
65
Ethical implications of using untested drugs during epidemic
Drugs have not gone through full clinical trials Side effects could make the situation worse Deciding who gets the vaccine is hard Informed consent is an issue Less trust between health workers and communities
66
What is translocation mutation - types
When a piece from a pair of chromosomes breaks off and reattached to one of a completely different pair. Can be balanced or unbalanced.
67
What is non disjunction of chromosomes - examples to know
When whole chromosome is affected Monosomy or polysomy. Down syndrome is polysomy of chromosome 21 Turners syndrome is monosomy - extra sex chromosome Aneuploidy is no chromosomes present = death
68
Development of embryo to blastocyst
Embryo Cleavage is rapid replication with no growth to form blastocyst
69
Formation of pollen in plant and how it changes
In pollen sacs there are microspore mother cells Divide by meiosis to form haploid microspores these undergo mitosis. Each gamete contains tube nucleus and generative nucleus which then undergoes final mitosis before fertilising
70
Formation of egg cells in plant
Diploid megaspore mother cells divide by meiosis to produce haploid megaspores, three of these degenerate 3 x mitosis to produce embryo sac egg cell, 2 polar nuclei, and other cells
71
fertilisation process in plants
Stigma will recognise correct pollen Pollen tube grows. Generative nucleus does mitosis. One male nucleus fuses with polar nuclei to form triploid endosperm nucleus (food) and other fuses with the egg cell to form zygote
72

Biology B (11 decks)

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