CB1, CB2: Key Concepts & Cells Flashcards
(84 cards)
1
Q
What organelles are found in animal cells, and what are their functions?
A
- Ribosomes (synthesise proteins)
- cell membrane (controls what enters and exits the cell)
- cytoplasm (where chemical reactions take place)
- nucleus (controls the cell and contains DNA)
- mitochondria (where aerobic respiration takes place)
2
Q
What organelles are found in plant cells, and what are their functions?
A
- Nucleus (controls the cell and contains DNA)
- cellulose cell wall (provides strength and support
- cell membrane (controls what enters and exits the cell)
- cytoplasm (where chemical reactions take place)
- chloroplasts (where photosynthesis takes place)
- permanent vacuole (cell sap storage)
- mitochondria (where aerobic respiration takes place)
- ribosomes (synthesise proteins)
3
Q
Total magnification = ?
A
eyepiece lens * objective lens
4
Q
magnification
A
the process of enlarging an image
5
Q
What is the resolution?
A
the ability to distinguish between two points
6
Q
Image size = ?
A
actual size * total magnification
7
Q
How is a sperm cell specialised?
A
- streamlined shape - easier to swim
- acrosome - contains special enzymes to penetrate the egg
- midpiece - contains mitochondria to release lots of energy
- haploid nucleus
- tail - it can swim
8
Q
How is an egg cell specialised?
A
- contains nutrients for an embryo in the cytoplasm
- its cell membrane becomes strong once it has been fertilised so that it cannot be fertilised twice
9
Q
How is a ciliated epithelial cell specialised?
A
- the cells have many cilia (little hairs) to sweep mucus along the trachea
10
Q
What’s the difference between eukaryotic cells and prokaryotic cells?
A
Prokaryotic cells have no membrane-bound organelles (eg: nucleus, mitochondria, chloroplasts)
11
Q
What are the features of a bacterial cell?
A
- prokaryotic
- flagellum enables it to swim
- plasma membrane
- capsule - often associated with pathogens
- plasmid - small extra bit of DNA which can replicate independantly
- nucleoid - region in the cell containing most of the DNA
- pili - hollow hair-like appendages which allow it to attach to other cells
12
Q
What does a salivary gland do?
A
produces saliva, which contains enzymes
13
Q
oesophagus
A
carries food from the mouth to the stomach
14
Q
liver
A
breaks down fats and old blood cells
15
Q
gallbladder
A
stores bile
16
Q
stomach
A
churns the food
17
Q
pancreas
A
produces enzymes
18
Q
small intestine
A
absorbs small food particles
19
Q
large intestine
A
absorbs excess water into the body
20
Q
rectum
A
stores waste before it exits
21
Q
anus
A
the way out
22
Q
physical digestion
A
breaking large pieces of food into small pieces of food (eg: stomach churning food)
23
Q
chemical digestion
A
breaking down large molecules (eg: starch) into small molecules (eg: glucose). Requires enzymes - biological catalysts
24
Q
protease
A
breaks protein down into amino acids
25
lipase
breaks lipids (fats) down into fatty acids and glycerol
26
amylase
breaks down starch into glucose
27
bile
emulsifies fats
28
enzymes are...
biological catalysts
29
enzymes are sensitive to...
pH and high temperature
30
Lock and key model
The substrate fits into the active site because it is specific and has a complementary shape.
31
Diffusion
moving a substance from an area of high concentration to an area of low concentration (along the concentration gradient)
32
Osmosis
diffusion of water across a semi-permiable membrane. Affected by the presence of salt.
33
Active transport
movement of ions against the concentration gradient.
34
concentration gradient
moving from an area with high concentration to an area with low concentration
35
Fick's law
rate of diffusion = (concentration gradient * SA)/membrane thickness
36
diploid cell
a cell with two of every chromosome
37
haploid cell
a cell with half the number of chromosomes
38
What does mitosis produce?
two genetically identical daughter cells
39
Why does mitosis take place?
Cells need to divide for growth and repair
40
What process creates more sperm and egg cells?
Meiosis
41
What is the cell cycle?
1. Growth
2. DNA synthesis: DNA replicates to form two copies of each chromosome
3. Mitosis
42
How does asexual reproduction work?
It uses mitosis
43
What are the phases of mitosis?
(I)PMATC
* Interphase
* prophase
* metaphase
* anaphase
* telephase (cytokenesis)
44
Interphase is...
when each chromosome is copied
45
prophase is...
when the nucleus gets dismantled
46
metaphase is...
when the chromosomes line up in the centre
47
anaphase is...
when the chromosomes seperate
48
telephase/cytokenesis is...
How are plant cells different?
The chromosomes reach the poles in telophase.
The cells seperate in cytokenesis - plants don't do this
49
Why is there controversy around stem cells?
* Some Christians are against embryonic stem cell use because they believe life begins at conception
50
Where are stem cells found?
In plants: meristems
In humans/animals: embryos, (can also be found in most parts of the body, but can only specialise into the surrounding tissue)
51
Why are embryonic stem cells really useful?
They can specialise into anything
52
Explain growth percentiles
20th percentile: lowest 20%
80th percentile: lowest 80%/top 20%
50th percentile: completely average; lowest 50%, highest 50%
53
reflex actions
automatic actions that don't require conscious thought
54
cerebral cortex
The largest part of the brain. Made of hemispheres. Covered by grey matter called cerebral which is important for intelligence.
* language
* memory
* thought
* reason
* learning
*consciousness
55
cerebellum
The second largest part of the brain. Rear lower part of the brain. Impulses for coordinated movement.
* balance
* movement coordination
* vision
* posture
56
medulla oblongata
Connects brain stem to the brain. Controls coughing, sneezing, swallowing, and hiccuping. Vital for essential bodily functions.
* heartbeat
* breathing
* vomiting
* maintaining blood pressure
57
Pros and cons of CT scans
Machine using X-rays from multiple angles to create a cross-section.
* only scans tissues and organs
* can damage DNA
* dye used can cause kidney problems
58
Pros and cons of PET scans
Patient ingests radioactive glucose. The machine detects photons emmitted by this.
* can show what is working and what is not
* helps check for cancer
* checks for abnormalities
* radiation exposure
59
Spinal cord damage treatment
Surgery:
* remove fluid or tissue that presses on the spinal cord
* remove bone fragments, disc fragments, or foreign objects
* fuse broken bones
* place spinal braces
60
What are neurones also known as?
nerves
61
sensory neurone
from sensory receptor to brain and spinal cord.
the "input"
62
synapse
the functional gap between neurones
63
motor neurones
from brain and spine to muscles and glands
the "output"
64
intermediate neurones
carry information between neurones - only found in the brain or in the spinal cord
65
What is the reflex arc?
Stimulus -> Receptor -> Sensory neurone -> Central nervous system (CNS) -> Motor neurone -> Effector -> Response
66
What is the formula for average speed?
Speed = distance/time
67
Why are reflexes faster?
There's a shorter distance.
S=D/T
68
How does the mammalian eye get light into impulses?
Photoreceptors function as transducers in converting the energy of light stimuli into the code of the nervous impulse.
69
transducer
turns energy from one form to another
70
What are the two kinds of photoreceptors in the mammalian eye?
Rods and cones
71
What are rods for?
"Night vision"
72
What are cones for?
"Colour vision"
73
cornea
protective layer over the pupil
74
pupil
hole which lets in light
75
sclera
stops too much light getting in
76
iris
expands or contracts the pupil - changes the APERTURE
77
Why is the back of the eye black?
It absorbs colour
78
Why is the sclera white?
otherwise it would let in too much light
79
When there is bright light, what size does the pupil become and why?
Small to lower the amount of light reaching the photoreceptors
80
When there is low light, what size does the pupil become and why?
Large to increase the amount of light reaching the photoreceptors
81
What shape is the lens in the eye? What does it try to do?
Biconvex (converging)
Focusses light onto the **fovea centralis**
82
What does a thin lens do?
Bends light less, and causes longsightedness
83
What does a fat lens do?
Bends light more, and causes shortsightedness
84
circular muscles...
radial muscles...
circular muscles - contract during pupil constriction, and relax during dilation
radial muscles - contract in dilation, and relax in constriction
