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Flashcards in Cell Structure Deck (50):
1

Cibosomes?

Where protein synthesis occurs

2

Mitochondria?

Where most of the energy is released in respiration

3

Cell membrane?

Controls the passage of substances that come in & out of the cell

4

Nucleus?

Controls activities of the cell

5

Cytoplasm?

Most chemical reactions take place here (controlled by enzymes inside cells)

6

Vacuole?

Filled with cell sap and when full supports the cell

7

Chloroplasts?

absorbs light for photosynthesis

8

Cellulose cell wall?

Strengthens the cell

9

1m/1000

1mm

10

1mm/1000

1um

11

1um/1000

1nm

12

1mm =

1000um

13

1mm = nm?

1000000 1x106

14

How long are eukaryotic cells?

10-100um

15

How long are red blood cells?

8um

16

What are prokaryotic cells?

Unicellular with no nucleus and much smaller than eukaryotic cells e.g bacteria & blue green algae

17

How long are bacterial cells?

2-8um

Eukaryotic cells are about 10x bigger

18

Flagellum?

Small whip like tail for propulsion

19

Plasmid?

Possess genes which may aid the survival of bacteria

20

Chromosomal DNA?

genetic info for replication of the cell

21

Cell surface membrane?

permeable barrier

controls exit & entry of chemicals

22

Capsule?

Protection and helps bacteria to adhere to each other

23

Cell wall?

Physical barrier

Protects against damage and osmotic lysis

24

Magnification?

magnification (m) = size of image(I) / actual size of specimen


25

Magnification is?

Objective lens x eyepiece lens

26

What are stem cells?

Replicate themselves
Differentiate into many cell types

27

Stem cells in animals?

Embryonic stem cells

Unspecialised
Can differentiate into any cell in the body

Umbilical chord found

28

Adult stem cells?

Found in the bone marrow

Divide to repair

Replace damaged tissue

29

Stem cells in plants?

Non specialised stem cells are found in the meristems of plants

30

Meristems?

Found at tips of roots & shoots & in between the xylem & the phloem tissues

Can divide over and over to produce non specialised stem cells

Some continue to divide making the plant talked and wider

Can develope into any type of specialised plant cell and go on to form phloem , xylem, leaves and flowers

31

Pattern of growth?

Plants - often grow continuously
Animals- grow to a maximum size

32

How growth hAppens?

Plants-by cell enlargement
Animals- increasing no. Of cells

33

Where cell division happens?

Plants-at meristems
Animals-in most tissues

34

Cell differentiation?

Plants- many cells can differentiate
Animals- most cells lose ability to differentiate at an early stage

35

Stem cells in medical research?

Pros

-diseases can be treated
-regenerate nerves
-model diseases

Cons

-embryo will die
-lack of research
-unsure of long term side affects
-body could reject if not self tissue
-difficult & long procedure
-donation requires license

36

What is mitosis?

Cell division in eukaryotic cells, they divide to produce two new identical copies

37

What are chromosomes?

Contain genetic info

38

Mutation?

Change in your genetic makeup

39

What are cancer cells?

Arise due to mutations in genes that control cell growth (mitosis) this leads to uncontrolled cell growth and results in a tumor

40

What is diffusion?

The random movement of particles from an area of high concentration to an area of low concentration i.e down a concentration gradient. Continues until the particles are at an even concentration

41

Where does diffusion occur?

Gas exchange in lungs
Gas exchange in leaf
Materials across capillaries
Substances across placenta

42

Factors affecting the rate of diffusion?

Temp- increase in temp means more kinetic energy for particles, more quickly so diffusion quicker

SA-bigger sa so more molecules can be diffused

Thickness of gradient pathway- the thinner the diffusion surface the faster the molecules will diffuse

Concentration gradient- steep only one side moves, shallow both sides move

43

What is osmosis?

The diffusion of water from a dilute to a more concentrated solution through a partially permeable membrane that allows the passage of water molecules

44

Osmosis in animal cells?

When RBC is put in dilute, water will enter by osmosis, RBC fills up, swell & burst (lysis)

When RBC is put in concentrated solution, water will leave by osmosis, RBC will shrivel (crenation)

45

Osmosis in plant cells?

The cell wall prevents from bursting (lysis)

Placed in more concentrated, water will leave cell by osmosis, cell membrane pulls away from the cell wall & plant is plasmalysed.

Placed in dilute e.g sugar, water will enter by osmosis, will fill up but won't burst, cell wall will stretch, plant is turgid

Swell = turgid
Shrivel = plasmalysed

46

What is active transport?

Cells may need to absorb substances that are in short supply. Transport Substances across a partially permeable membrane against the concentration gradient low to high using a carrier protein and energy. This happens from respiration.

47

What happens in active transport?

Molecules bind to carrier protein & energy from respiratiOn allows the molecule to cross the membrane

48

Active transport in living systems?

Glucose can be reabsorbed into the kidney tubules.

Obtain mineral ions through root hair cells

Na+ & K+ actively transported in neurons(nerve cells)

49

What do cells involved in active transport contain?

Lots of mitochondria BC lots of energy is needed to cross membrane

50

What is a eukaryotic cell?

Contains a true nucleus & other organelles which are enclosed within membrane e.g plant and animal cells