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Gd 10 - Life Sciences 2017 > Cells > Flashcards

Flashcards in Cells Deck (41):
1

Three original tenets of cell theory

  1. All living things consist of cells
  2. The cell is the smallest and basic unit of life
  3. All cells originate from pre-existing cells

2

Tenets of modern Cell Theory

  1. All living things consist of cells
  2. The cell is the smallest and basic unit of life
  3. All cells originate from pre-existing cells

Modern additions:

  1. The activity of an organism depends on the total activity of independent cells.
  2. Energy flow (metabolism and biochemistry) occurs within cells.
  3. Cells contain DNA, the hereditary information.
  4. All cells are basically the same in chemical composition in organisms of similar species.

3

Function of chromatin network

  • Made of DNA and proteins
  • Contains genes (hereditary information)
  • Instructs all the activities of the cell
  • Packaged as chromosomes for cell division

4

All eukaryotic cells have...

  • Cell membrane
  • Cytoplasm
  • Organelles
  • Nucleus

5

Only plant cells have...

  • Cell wall (though fungi also have a cell wall)
  • Large central vacuole
  • Plastids e.g. chloroplasts

6

Structures making up the cell wall of plants

  • Primary cellulose wall
  • Secondary lignin wall
  • Middle pectin lamella
  • Pits
  • Plasmodesmata

7

Primary cellulose wall function

shape

8

Secondary lignin wall function

strength

9

Middle pectin lamella function

joins cells together

10

Pits in cell wall function

ease transport between cells

11

Plasmodesmata function

joint cell cytoplasms for communication and transport between plant cells

12

Useful substances made from plant cell walls

  • Wood
  • Paper
  • Cork
  • Cotton

13

Structures of cell membranes

  • Phospholipid bi-layer
  • Carrier and channel proteins
  • Carbohydrates

14

Function of carrier and channel proteins in a cell membrane

control movement of larger substances into and out of a cell

15

Function of the carbohydrates on the surface of a cell membrane

cell recognition

16

Parts of the phospholipid bi-layer

  • Hydrophilic head
  • Hydrophobic tail
  • Hydrophobic tail
  • Hydrophilic head

17

Types of movement across a membrane

Diffusion

Osmosis

Facilitated transport

Active transport

18

Two types of osmosis

Endosmosis (water movement into cell)

Exosmosis (water movement out of cell)

19

Process of diffusion

  • Passive process (no energy required)
  • Non-selective movement along concentration gradient
  • From high to low concentrations until equilibrium
  • E.g. oxygen

20

Process of osmosis

  • Selectively permeable membrane
  • Passive process (no energy required)
  • Movement of water into or out of cell
  • Water moves along concentration gradient
  • From high water potential to low water potential until equilibrium

21

Process of facilitated transport

  • Living selectively permeable membrane
  • Carrier proteins required
  • passive process (no energy required)
  • selective movement of substances along concentration gradient using carrier proteins until equilibrium
  • e.g. Glucose

22

Process of active transport

  • living selectively permeable membrane
  • carrier proteins required
  • active process ATP required
  • selective movement of substances
  • against a concentration gradient (from low to high)
  • e.g. sodium and potassium ions

23

Endocytosis

  • In animal cells
  • Process of taking in food particles and nutrients
  • Also called phagocytosis
  • structure formed called a food vacuole (membrane bound)

24

Exocytosis

-In animal cells

-structure involved called secretory vesicle (membrane bound)

-Process or removing particles and metabolic wastes

-Also called elimination or secretion

25

Other cell membrane structures in animal cells

Microvilli - increase surface area

Pinocytic vesicles - take up liquids

Phagocytic vesicles - take up particles using pseudopodia

26

Structures of the nucleus

Double membrane

Nucleopores

Nucleoplasm

Chromatin network

Nucleolus

27

Two types of endoplasmic reticulum (ER)

Smooth ER - no ribosomes attached

Rough ER - ribosomes attached

28

Function of the endoplasmic reticulum

Connects cell membrane with nucleus

A network of membrane bound tubes

For transporting substances

Rough ER makes and transports proteins

29

Cytoplasm contents

-Water (90%)

-Enzymes

-Protein cytoskeleton

-Organelles

30

Function of ribosomes

Protein synthesis

31

Examples of vacuoles

Contractile vacuole - controls water content of cell

Lysosome - contains peroxidase enzyme

Phagocytic vesicle - contain food particles

Pinocytic vesicle - take up fluids

32

Tonoplast

Membrane that surrounds a vacuole

It can provide turgidity (support) to the cells

33

Structure of a mitochondrion

  • Double membrane
  • Cristae - internal folds
  • Matrix - internal fluid

34

Function of the mitochondrion

  • Where cellular respiration takes place
  • Production of ATP (energy carrier molecules)
  • Provides energy for the cell

35

Golgi body (animal cells) and dictyosomes (plants) structure and function

Stacked flapjack like membrane bound structure

Packaging centre of cell

Sort and store cellular secretions e.g. enzymes

36

Types of plastids (plant cells)

  • Leucoplasts - no pigments (storage organelle)
  • Chromoplasts - yellow-red pigments
  • Chloroplasts - green pigments

37

Structure of a chloroplast

  • Double membrane
  • Stroma - inner fluid
  • Thylakoids - membrane structures with chlorophyl
  • Grana - stacked thylakoids
  • Inter-granum lamella - membrane bridges between grana
  • Occasionally: starch granules

38

Chlorophyll

  • Green pigment
  • Captures light energy
  • Needed for photosynthesis

39

Structure and function of the centrosome

  • Made of two centrioles
  • act as anchors during cell division
  • and form the spindle apparatus

40

Cell differentiation

  • A process where cells change size, shape and composition
  • to be able to perform specific function
  • also called cell specialisation

41

Undifferentiated cells in plants and animals

  • Stem cells - animals
  • Meristem cells - plants