Cell: Unit Of Life Flashcards

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1
Q

What is a cell?

A

A cell is a structural and functional unit of all living beings

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2
Q

The first microscope was created by?

A

Antony Van Leeuwenhoek

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3
Q

Simple microscopes consisted?

A

Single Biconvex lens

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4
Q

Who created a microscope with 2 lenses?

A

Robert Hooke

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5
Q

State the 3 main points of cell theory.

A

1.The cell is the smallest unit of structure of all living things
2. The cell is the unit of function of all living things
3. All cells arise from pre-existing cells.

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6
Q

Name some single-celled organisms

A

Bacteria , Amoeba, Yeast

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7
Q

Name some few-celled organisms

A

Spirogyra, Volvox

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8
Q

Name some multi-celled organisms

A

Human beings, Mango

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9
Q

The smallest cell

A

Bacteria, RBC

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10
Q

Longest cells

A

Nerve cells

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11
Q

Largest cells

A

Bird’s eggs, ostrich eggs

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12
Q

Why are cells small in size?

A
  1. different regions can communicate with each other rapidly for the cell to function effectively
  2. Cells have large surface area/volume ratio for greater diffusion of substances in and out of the cell.
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13
Q

Shape of Human RBC

A

circular and biconcave( to pass through narrow capillaries and transport o2)

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14
Q

Shape of WBC

A

Amoeboid(squeeze out through capillary walls)

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15
Q

Shape of Nerve cells

A

long(to conduct impulses)

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16
Q

Shape of Muscle cells

A

long and contractile( to pull or squeeze the parts)

17
Q

Shape of Guard Cells

A

bean shaped( to open and close the pores)

18
Q

Differentiate between cell wall and cell membrane

A

Cell membrane-
1. Fine pores through which substances may enter or leave the cell.
2. Permeability is selective
CELL WALL-
1. Plants have cell wall
2.Gives shape and rigidity
3. Freely permeable

19
Q

Explain cytoplasm

A

1.Semi-liquid substances
2.Colourless,partly transparent and somewhat watery
3.Many chemical reactions take place here
4. Living cytoplasm

20
Q

Explain Endoplasmic Reticulum

A

1.Revealed only through an electron microscope
2.ER is an irregular network of double membranes distributed over the entire cytoplasmic
3. At the outer end E.R is connected with the cell membrane
4.In the inner end it is connected with the nuclear membrane
5. It appears rough with ribosomes but smooth without it.
6. it forms a supporting framework of the cell and also serves as a pathway for the distribution of the material from one part of the cell to another.

21
Q

Explain ribosomes

A
  1. Numerous small granules
  2. Either scattered freely in the cytoplasm or attached to the E.R
  3. These are factories for the synthesis of protiens.
22
Q

Explain Mitochondria

A
  1. Spherical, rod-shaped or thread like structures
  2. Double walled bags with thier inner wall produced into finger like processes projecting inwards.
  3. It is where cell respiration occurs to release energy.
  4. The energy is stored in the form of ATP. Atp is used in various metabolic functions of the cells
23
Q

Explain Golgi Apparatus

A
  1. Granules, Filaments or rods
  2. They are supposed to originate from the E.R
  3. Usually located near the nucleus
  4. It is concerned with the sectretions of the cell including enzymes and hormones
24
Q

Explain Lysosomes

A
  1. Contain digestive enzymes
  2. Their enzymes destroy and digest foreign substances around them.
  3. The digest the stored food during starvation of the cell.
  4. Many damaged cells are repeatedly destroyed or dissolved by their own lysosomes and hence these are called “sucide bags”
25
Q

Centrosomes and Centrioles

A
  1. Centrosomes are only found in animal cells
  2. The centrosomes contain 2 centrioles which are small bundles of microfilaments arranged at right angles to each other.
  3. These are not present in plant cells.
26
Q

Explain plastids

A
  1. only found in plant cells
  2. There are divided into 3 based on the colour
    - Leucoplasts(White)
    -Chromoplasts(Yellow,orange and red)
    -Chloroplasts(Green)
27
Q

Explain Leucoplasts

A
  1. Colorless plastids
    2.Have no pigment
    3.Store Starch
    4.Cells of potato have lots of leucoplasts in them
28
Q

Explain Chromoplasts

A
  1. Present in petals of flowers and fruits
    2.xanthophyll- yellow
  2. Carotene- Orange and red
29
Q

What are anthocyanins?

A

Anthocyanins are a group of pigments found in plants that give them their red, purple, and blue colors.

30
Q

Explain chloroplasts

A
  • They have chlorophyll
    -Function: Trap solar energy and absorb carbon dioxide for the manufacture of starch and sugar during photosynthesis
  • They contain DNA and the capacity to divide
31
Q

Are granules living or non-living? Explain

A

Nonliving. They are present in the cytoplasm and contain food materials such as starch glycogem and fats

32
Q

Vacuoles

A

-Cytoplasm
-In plant cells they are large and contain cell sap
- certain clear spaces in the cytoplasm

33
Q

Nucleus Functions

A
  • Regulates and co-ordinates various life processes
  • Plays and imp part in the cell div
  • Contains genes
34
Q

Explain chromatin fibres

A
  • Thread-like
  • Present in nucleoplasm
  • During cell div they become thick and ribbon -like and are called chromosomes
35
Q

What does the nucleolus do?

A

Partcipare in protien synthesis of ribosomes

36
Q

What is protoplasm?

A

It is the total living substance that is the cytoplasm and nucleus. It is a translucent fluid somewhat colourless, geyish or brown

37
Q

Composition of protoplasm

A

C,O,H,N,S,Fe all present in specifci compouns like water, protiens, carbs, fats and mineral salts