Biology - 2.1 - Flashcards in A Level and IB Biology

What are the benefits of Light Microscopes?

cheap, easy to use, portable, able to study WHOLE LIVING ORGANISMS

1 of 40

How do electron microscopes work?

they use a beam of fast travelling electrons with a wavelength of 0.004nm. (1)electrons are fired from a cathode and focused by magnets. (2) fast travelling electrons have a wavelength 125,000 times smaller than visible light (400-700nm)

2 of 40

Drawbacks of electron microscopes?

large and very expensive. require skill and training to use

3 of 40

How to go from metres (m) to pica-metres (pm)

m x100 = cm x10 = mm x1000 = um x1000 = nm x1000 = pm

4 of 40

Must-Dos for Biological Drawings

at least 50% of paper, single continuous label lines used, ruled label lines (horizontal, no arrows) , main structures are labelled, title, accurate representation, sharp pencil, annotation about colour, magnification

5 of 40

How to calibrate an eyepiece graticule using the stage micrometer

(1) Align the EPG and the SM (2) record how many EPG divisions are the same value as the whole SM (3) Divide 1000um by the no of divisions, to give how many micrometres (um) is measured by 1 division on the EPG

6 of 40

How do Transmission Electron Microscopes work?

(1) the specimen is chemically fixed by being dehydrated and stained with metal salts. (2) the beam of electrons PASSES THROUGH the specimen and then focused on a screen

7 of 40

How do Scanning Electron Microscopes work?

(1) the specimen is placed in a vacuum and coated in a fine film of metal (2) the electrons do not pass through the specimen, but cause secondary electrons to bounce off of the specimen

8 of 40

The Structure of the Nucleus, Nuclear Envelope + Nucleolus

(1) double membrane (2) nucleolus has no membrane, is filled with RNA (3) the genetic material is chromatin, containing DNA wound around histone proteins

9 of 40

Function of Nucleus, Nuclear Envelope + Nucleolus

(1) nuclear envelope separates contents from rest of cell (2) pores enable large substances, rRNA, to enter and leave (3) nucleolus is where ribosomes are made (4) chromosomes contain the genome

10 of 40

Structure of RER

(1) system of membranes containing fluid filled CISTERNAE, continuous with nuclear membranes (2) coated in ribosomes

11 of 40

Function of RER

(1) the intracellular transport system - cisternae form channels (2) provides large surface area for ribosomes, which pass through membrane, into cisternae, and out to the golgi apparatus

12 of 40

Structure of SER

(1) a system of membranes containing cisternae that are continuous with the nuclear membrane (2) no ribosomes

13 of 40

Function of SER

(1) contains enzymes involved with lipid metabolism and the synthesis of cholesterol/lipids/phospholipids/steroid hormones (2) involved in absorption, synthesis and transport of lipids

14 of 40

Structure of Golgi Apparatus

(1) a stack of membrane bound flattened sacs (2) secretory vesicles bring material to and from

15 of 40

Function of Golgi Apparatus

(1) MODIFIES proteins by adding sugar molecules to make glycoproteins, adding lipid molecules to make lipoproteins, fold proteins into 3D shape. (2) PACKAGES proteins into vesicles that are either stored or excreted from cell

16 of 40

Structure of Chloroplasts

(1) double membrane (2) inner membrane is continuous with stacks of flattened membrane sacs called THYLAKOIDS (3) each stack called a GRANUM and contains a fluid filled matrix called the STROMA (4) they contain loops of DNA + starch grains

17 of 40

Function of Chloroplasts

(1) the site of photosynthesis (2) light energy is trapped by chlorophyll and used to make ATP, happens in the grona. water is made into H+ ions (3) hydrogen reduces CO2 using ATP to make carbs, happens in STROMA

18 of 40

Structure of Mitochondria

(1) surrounded by 2 membranes with a fluid filled CISTERNAE. (2) inner membrane is highly folded into CRISTAE (3) inner part of mitochondrion is a fluid filled matrix

19 of 40

Function of Mitochondria

(1) site of ATP production using aerobic respiration (2) self-replicating ~ more produced if energy need increases (3) abundant in very metabolically active cells

20 of 40

Structure of Vacuole

(1) surrounded by membrane celled TONOPLAST (2) contains fluid

21 of 40

Function of Vacuole

(1) filled with water and solutes and maintains cell stability (2) when full it pushes against cell wall, making the cell turgid (3) if all cells turgid, this supports the plant

22 of 40

Structure of Lysosomes

(1) small bags formed from golgi apparatus, each surrounded by single membrane (2) contains powerful hydrolytic enzymes (3) abundant in phagocytic cells that ingest + digest pathogens

23 of 40

Function of Lysosomes

(1) keep powerful enzymes separate from rest of cell (2) can engulf old cell organelles and foreign matter, digest it, and return the components for reuse

24 of 40

Structure of Cilia and Undulipodia

(1) protrusions from the cell surrounded by the plasma membrane (2) each contain microtubules (3) form from centrioles

25 of 40

Function of Cilia and Undulipodia

(1) cilia used to move mucus in epithelial cells (2) all cells have one cilium acting as an antenna - it contains receptors and detects changes (3) spermatozoon has big undulipodium

26 of 40

Structure of Ribosomes

(1) made of RNA (2) made in nucleolus in 2 subunits, pass out into cytoplasm then combine (3) some float free, most sit on RER

27 of 40

Function of Ribosomes

(1) ribosomes on RER used for synthesising proteins that are transported out of the cell (2) ribosomes in cytoplams are site for synthesising proteins for use inside the cell

28 of 40

Structure of Centrioles

(1) consists of 2 bundles of microtubules at RIGHT ANGLES to each other (2) microtubules are made of the tubulin protein subunit and are arranged to form a cylinder

29 of 40

Function of Centrioles

(1) spindle in cell division is made her (2) motor proteins walk along the centrioles, pulling chromosomes to one side (3) involved in the formation of cilia+undulipodia

30 of 40

Structure of Cytoskeleton

(1) a network of protein structures (2) rod-like microfilaments are made from the protein actin (3) straight cylindrical microtubules are made from tubulin (4) the cytoskeletal motor proteins are molecular motors.

31 of 40

Function of Cytoskeleton

(1) protein microfilaments give support and strength. maintain cell shape (2) microtubules provide shape + support. they form the track that motor proteins walk along, transporting organelles. form the spindle before the cell divides. make cilia

32 of 40

Structure of Cellulose Cell Wall

(1) on outside of the plasma membrane (2) made from cellulose fibres

33 of 40

Function of Cellulose Cell Wall

(1) strong, prevent bursting when turgid. strength. support, maintain shape. permeable

34 of 40

Features of Prokaryotic Cells

(1) PILI - small, hair like structures allowing bacteria to adhere to host cells. (2) NUCLEOID - area in cytoplasm where DNA is positioned. (3) Cell wall is made from PEPTIDOGLYCAN. (4) they have a waxy, protective cuticle (5) plasmids (6) FLAGELLA

35 of 40

All eukaryotic cells have......

(1) a nucleus surrounded by nuclear envelope (2) a nucleolus containing RNA (3) jelly cytoplasm (4) cytoskeleton (5) plasma membrane (6) vesicles (7) ribosomes

36 of 40

Prokaryote v Eukaryote ; Similarities

plasma membrane, cytoplasm, ribosomes, DNA, RNA

37 of 40

Prokaryote v Eukaryote ; Differences

Prokaryotes are/have: smaller, less developed cytoskeleton (no centrioles), no nucleus, no membrane bound organelles, peptidoglycan cell wall, protective waxy cuticle, flagella, divide by binary fission, smaller ribosomes, DNA in plasmid, pili

38 of 40

MAKING + SECRETING A PROTEIN (up to golgi)

(1) gene is transcribed onto length of mRNA + copies made (2) mRNA passes out nuclear pores into ribosomes (3) protein synthesised (4) protein passes into cisternae of RER (5) vesicle pinched off from RER and pass via microtubules to the Golgi

39 of 40

MAKING + SECRETING A PROTEIN (golgi onwards)

(6) Vesicle fuses with golgi apparatus, protein modified or repackaged (7) new protein in vesicle again, moves to plasma membrane (8) vesicle fuses via exocytosis and protein is secreted

40 of 40

Get Revising

Biology - 2.1

Other cards in this set

Card 2

Front

Back

Card 3

Front

Back

Card 4

Front

Back

Card 5

Front

Back

Comments

Similar Biology resources:

Other cards in this set

Card 2

Front

Back

Card 3

Front

Back

Card 4

Front

Back

Card 5

Front

Back

Comments

Related discussions on The Student Room

Similar Biology resources: