CB1: Key Concepts in Biology Flashcards

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1
Q

Define Magnification

A

The ability to enlarge smaller object’s appearance

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2
Q

What is the formula to calculate magnification using the two lenses?

A

eyepiece lens x objective lens

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3
Q

How do you calculate magnification based off of image size?

A

magnification = image size/ actual size

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4
Q

Define resolution

A

How detailed an image is

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5
Q

What is the difference between a light microscope and an electron microscope?

A

A light microscope uses light to display enlarged images and has a lower resolution as compared to an electron microscope. An electron microscope uses electrons to display images and has a higher resolving power than the light microscope

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6
Q

What is the limitation of an electron microscope?

A

You can’t observe living things because samples are placed in vacuums

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7
Q

What is the difference between a prokaryotic and eukaryotic cell?

A

Eukaryotic cells: cells with a nucleus eg: animal and plant cells
Prokaryotic cells: cells without a nucleus eg: bacteria

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8
Q

What is the role of the nucleus?

A
  • controls the cell and its activities
  • contains chromosomes
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9
Q

What is the role of the cell membrane?

A
  • thin bag
  • controls what enters and leaves
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10
Q

What is the role of the mitochondria?

A

Where aerobic respiration occurs

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11
Q

What is the role of the ribosomes?

A

Makes proteins for the cells

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12
Q

What is the role of the chloroplasts?

A
  • contain chlorophyll
  • traps energy from the sun to be used in photosynthesis
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13
Q

What is the role of the cell wall?

A
  • made of cellulose
  • supports and protects the cell
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14
Q

What is the role of the vacuole?

A
  • stores cell sap
  • helps keep the cell rigid and firm
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15
Q

Define specialised cells

A

Cells with specific functions/ jobs

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16
Q

What are the adaptations of an egg cell?

A
  • haploid for fertilisation to make a diploid cell
  • jelly coat protects the egg and hardens after fertilisation to prevent other sperm cells from entering
  • cell membrane: fuses with the sperm cell membrane. also hardens after fertilisation to prevent other sperm cells from entering
  • cytoplasm: packed with nutrients to supply fertilised egg cell with energy and raw materials for growth and development of embryo
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17
Q

What are the adaptations of a sperm cell?

A
  • haploid
  • streamlined shape: helps it to swim faster
  • lots of mitochondria: releases lots of energy
  • tail to move
  • acrosome: contains enzymes that break down substances in the jelly coat of the egg
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18
Q

What are the adaptations of ciliated epithelial cells?

A
  • cilia covered in cell membrane
  • contains strands of a substance that can contract and cause wavy movement
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19
Q

What is the role of the chromosomal DNA?

A
  • controls cells activities
  • found free in the cytoplasm
20
Q

What is the role of the plasmids?

A
  • controls some of the cell’s activities
  • extra DNA
21
Q

What is the role of the flagellum?

A
  • long thin ‘whip-like’ tails
  • so bacteria can move
22
Q

Define enzymes

A

Biological catalysts

23
Q

What is the role of an enzyme?

A

It can break down large substances into small ones (breakdown) and join small substances into larger ones (synthesis)

24
Q

What does protein break down into?

A

Amino acids

25
Q

What does starch break down into?

A

Glucose

26
Q

What do lipids break down into?

A

Fatty acids and glycerol

27
Q

What is the active site of an enzyme?

A

The part of the enzyme where the substrate fits into

28
Q

Explain the lock and key hypothesis

A

The shape of the active site matches the shape of its substrate, which forms an enzyme-substrate complex. Once bound, the reaction takes place on the enzymes surface.

29
Q

What happens when an enzyme becomes ‘denatured’?

A

The shape of the active site changes, so the substrate no longer fits in it

30
Q

What three conditions affect enzyme activity?

A
  • temperature
  • pH
  • substrate concentration
31
Q

What occurs to an enzyme when we pass its optimum temperature/ pH?

A

It becomes denatured

32
Q

What occurs to an enzyme when we pass its optimum substrate concentration?

A

All the enzymes become saturated, so increasing the substrate concentration after this point will have no affect on the enzymes themselves.

33
Q

How do we calculate rate?

A

change in measured substance / time it takes for change to be displayed

34
Q

Define diffusion

A

When particles move from an higher concentration to a lower concentration. It doesn’t require energy

35
Q

Define osmosis

A

The diffusion of solvents through a partially permeable membrane. It doesn’t require energy

36
Q

Define active transport

A

When cells transport molecules against a concentration gradient/ transport those that can’t fit through the partially permeable membrane. This requires energy

37
Q

How do you calculate the percentage change in mass?

A

((final mass - initial mass)/initial mass) x 100

38
Q

What enzyme causes the breakdown of carbohydrates?

A

Carbohydrases

39
Q

What enzyme causes the breakdown of proteins?

A

Protease

40
Q

What enzyme causes the breakdown of lipids?

A

Lipases

41
Q

What is a hypotonic solution?

A

More water than sugar

42
Q

What is an isotonic solution?

A

Equal amounts of water and sugar

43
Q

What is a hypertonic solution?

A

More sugar than water

44
Q

What is the difference between animal cells and plant cells in a hypotonic solution?

A

Animal cell: Lysed (cell membrane is broken or destroyed)
Plant cell: Turgid (tissues swollen by water uptake) normal

45
Q

What is the difference between animal cells and plant cells in an isotonic solution?

A

Animal cell: normal
Plant cell: flaccid (drooping/inelastic due to lack of water)

46
Q

What is the difference between animal cells and plant cells in a hypotonic solution?

A

Animal cell: shrivelled
Plant cell: plasmolysed (shrinking of the cytoplasm from the wall of the living cell due to the lack of water)