Topic 1 Cell Biology Flashcards
(103 cards)
1
Q
Where do most of the chemical reactions in a cell happen?
A
In the cytoplasm
2
Q
What is the function of the cell membrane?
A
It controls the movement of substances in and out the cell
3
Q
What is the function of the cell wall?
A
It strengthens the cell and supports the plant
4
Q
What is the function of the permanent vacuole?
A
It is filled with cell sap to help keep the cell turgid
5
Q
Where is genetic material found in a prokaryotic cell?
A
DNA is a single loopin cytoplasm and also in small rings called plasmids.
6
Q
Are prokaryotic cells bigger or smaller than eukaryotic cells?
A
Much smaller
7
Q
What is the size of a micrometre?
A
1/1,000,000th of a metre(1 millionth)
8
Q
What is the symbol for a micrometre?
A
Looks like an upside down h and an m
9
Q
What is a micrometre in standard form?
A
1x10(-6)m
10
Q
What is the size of a nanometre?
A
1/1,000,000,000th of a metre (1 billionth)
11
Q
What is the symbol for a nanometre?
A
nm
12
Q
What is a nanometre in standard form?
A
1x10(-9)m
13
Q
What is one order of magnitude?
A
10x greater
14
Q
What is two orders of magnitude?
A
100x greater
15
Q
What is three orders of magnitude?
A
1000x greater
16
Q
Are mitochondria larger or smaller than ribosomes?
A
Larger
17
Q
What is the vacuole filled with?
A
Cell sap
18
Q
What is cell differentiation?
A
When cells become specialised
19
Q
How are sperm cells adapted for fertilisation?
A
- head of the sperm contains genetic information
- tail and streamlined shape to swim to the egg
- mid piece packed with mitochondria- releases energy for swimming and fertilisation
- acrosome contains enzymes allow sperm to penetrate/digest way through eggs outer layer
20
Q
Where is the genetic information contained in a sperm cell?
A
In the nucleus in the head
21
Q
Where is the mitochondria contained in a sperm cell?
A
The mid piece/middle
22
Q
Where are the enzymes contained in a sperm cell?
A
In the acrosome (top of the head)
23
Q
What is the function of the mitochondria in a sperm cell?
A
Release energy needed to swim and fertilise the egg
24
Q
What is the function of the enzymes in a sperm cell?
A
Allow sperm to penetrate/digest their way through outer layer of the egg
25
What is the **function** of the **nerve cell**?
To **send electrical impulses** around the **body**
26
What is the **function** of **myelin**?
**Insulates** nerve cell and **increases speed** of **transmission** of **nerve impulses**
27
What is the **function** of **synapses** in a **nerve cell**?
**Junctions** (at the end of the axon) that allow **impulse to pass** from **one nerve cell to another**
28
What are **dendrites** in a **nerve cell**?
**Projections** from the **cell body**
29
What is the **function** of **dendrites**?
**Increase** the **surface area** available to **receive information** from **other nerve cells**
30
What are the **two ways muscle cells** are **adapted to contract**?
- contain **protein fibres**
- contain **mitochondria**
31
What is the **function** of **mitochondria** in a **muscle cell**?
**Provide energy** for **muscle contraction**
32
What is the **function** of **protein fibres** in a **muscle cell**?
Allow **muscle cell** to **contract** (**get shorter**)
33
What **plant cell organelle** does a **root hair cell not contain**?
**Chloroplasts** - root hair cells are underground
34
What is the **function** of the **root hair cell**?
To **absorb water** and **mineral ions**
35
How is the **root hair cell adapted** to **increase** the **rate of absorption**?
**large surface area**
36
Where are **xylem found**?
Plant **Stem**
37
What is the **function** of the **xylem**?
**Transport water** and **mineral ions** from **roots to leaves**
38
How are **xylem cells adapted** to **provide support** to the **plant**?
**Thick cell walls** containing **lignin**
39
How is the **xylem adapted** to **easily transport water** and **minerals**?
**Xylem cells** have **no end walls** and **no cytoplasm** so they form a **continuous hollow tube** allowing **substances to flow freely**
40
What is the **function** of the **phloem**?
**Transports products** of **photosynthesis up and down the plant**
41
Why do the **sieve tubes** in the **phloem have companion cells**?
**Sieve tubes** have **limited cytoplasm** so **contain little mitochondria** - **companion cells contain mitochondria**
42
What is the **function** of the **companion cells** in the **phloem**?
**Contain mitochondria** to **provide energy** for **transport** of **substances**
43
What are the **advantages** of **electron microscopes**?
- **higher magnification**
- **higher resolution**
44
How do **bacteria multiply**?
By **simple cell division**- **binary fission**
45
What is the **formula** to **calculate the number of bacteria in a population after a certain time if given the mean division time**?
**Number of bacteria = 2(to the power of n when n equals number of rounds of division)**
46
What are the **2 ways to culture bacteria**?
- in a **nutrient broth solution**
- as **colonies** on an **agar gel plate**
47
How many **chromosomes** does a **human body cell** have?
**23 pairs** or 46 in total
48
How many **chromosomes** do **gametes** have?
**23** (not paired)
49
What are the **stages** of **cell division called**?
**The cell cycle**
50
What is the **first stage** of the **cell cycle**?
- **DNA replicates** to form **two copies** of each **chromosome**
- **cell grows** and **copies it’s internal structures** eg mitochondria, ribosomes
51
What is the **second stage** of the **cell cycle**?
- (**mitosis**) **one set of chromosomes** is **pulled to each end of cell** and **nucleus divides**
52
What **stage** of the **cell cycle** is **mitosis**?
**Second stage**
53
What is the **third stage** of the **cell cycle**?
**Cytoplasm** and **cell membranes divide** to **form two identical cells**
54
What **types of cells** can **stem cells in bone marrow differentiate into**?
**Blood cells**
55
When are **bone marrow transplants used**?
- to **treat blood cancers** eg leukaemia
56
What are **stem cells**?
**Undifferentiated cells**, can **divide** to **produce more undifferentiated cells/different types of cells**
57
What are the **3 types of stem cells**?
**Embryonic**
**Adult**
**Meristem**
58
What can **stem cells from embryos and bone marrow be used for**?
**Cloned** and made to **differentiate** into **specialised cells** for **medicine/research**
59
Where are **adult stem cells found**?
**Only in certain places, bone marrow**
60
What can **adult stem cells do**?
**Form certain types of cell, blood cells**
61
What can **stem cells** from **bone marrow** be **used for in medicine**?
**Replace faulty blood cells**
62
What are **2 medical conditions** that can be **treated using stem cells**?
**Diabetes**
**Paralysis**
63
How can **embryonic stem cells** be used to **treat diabetes**?
**Make insulin-producing cells**
64
How can **embryonic stem cells** be used to **treat paralysis**?
**Make nerve cells**
65
What is **therapeutic cloning**?
**Embryo produced** with **same genes** as **patient**
66
Why is **therapeutic cloning useful** for **medical treatment**?
**Stem cells** from **embryo** have **same genes** so **not rejected by patients body**
67
What is a **risk** of **using stem cells in medicine**?
**Stem cells grown in lab** may become **contaminated** with **virus, transfer to patient**
68
Why are **some people against stem cell research**?
**Human embryos** are a **potential human life**
69
What is an **argument for stem cell research**?
**Embryos usually unwanted ones** from **fertility clinics**, would be **destroyed** if **not used for research**
70
Where are **stem cells found in plants**?
**Meristems**
71
What can **cells** in **meristem tissues do throughout the plants life**?
**Differentiate** into **any type** of **plant cell**
72
What can **stem cells** from **meristems be used for**?
**Produce clones** of **whole plants quickly** and **cheaply**
73
What are **2 things, cloning stem cells** from **meristems**, can be **used to do**?
**Rare species cloned** to **prevent extinction**
**Grow crops** of **identical plants** with **desired features** for **farmers (disease resistance)**
74
What is **diffusion**?
**Spreading out** of **particles** from **area of higher concentration** to an **area of lower concentration**
75
What **2 substances** does **diffusion happen in**?
**Solutions** and **gases**
76
Which **3 factors affect** the **rate of diffusion**?
**Concentration gradient (difference in concentration)**
**Temperature**
**Surface area** of **membrane**
77
How does a **bigger concentration gradient (difference in concentration) affect** the **diffusion rate**?
**Faster**
78
How does a **higher temperature affect** the **diffusion rate**?
**Faster- particles have more energy**
79
What can **only pass through cell membranes**?
**Small molecules**
80
What is **osmosis**?
**Movement of water** from **dilute solution** to **concentrated solution** across **partially permeable membrane**
81
What **type of movement** is **diffusion**?
**Random** and **net** (overall) movement
82
What is a **partially permeable membrane**?
**Very small holes** in it
83
What is **active transport**?
**Substances move** from **dilute solution** to **more concentrated solution against concentration gradient**
84
What does **active transport require**?
**Energy** from **respiration**
85
**When** is **active transport used** in the **gut**?
If **Lower concentration** of **sugar molecules** in **gut** but **higher concentration** of **sugar molecules** in **blood**
86
What does **active transport allow between blood** and the **gut**?
**Glucose taken into bloodstream** and **transported to cells** for **respiration**
87
How does the **waste product urea diffuse**?
From **cells** into **blood plasma** for **excretion by kidneys**
88
What are the **4 things** the **effectiveness** of an **exchange surface** are **increased by**?
**Large surface area**
**Thin membrane - short diffusion distance**
**Efficient blood supply** (in animals)
**Ventilated** gas exchange surfaces (in animals)
89
Why can **gases/dissolved substances diffuse directly** into a **single-celled organism**?
**Large surface area to volume ratio**
90
If an **organism is larger**, how is its **surface area to volume ratio affected**?
**Smaller**
91
What does the **ease** of an **organism** to **exchange substances with the environment depend on**?
**Surface area to volume ratio**
92
Why do **multicellular organisms need exchange surfaces**?
**Smaller surface area** compared to **volume- not enough substances** can **diffuse** from **outer surface** to **supply entire volume**
93
What is the **inside** of the **small intestine covered in**?
**Villi**
94
What do **villi** have to **assist quick absorption** of **digested food** into the **blood**?
**Network of capillaries** (good blood supply)
**Single layer** of **surface cells**
95
What is a **gas exchange surface in fish**?
**Gills**
96
What is **diffused** in the **gills**?
**Oxygen diffuses** from **water** into **blood**, **CO2 diffuses** from **blood** into **water**
97
What is **each gill made up of**?
**Lots of thin plates** called **gill filaments**
98
how are **gil filaments adapted** for **gas exchange**?
**large surface area, increased by lamellae**
99
what are **gil filaments covered in**?
**lots of tiny structures** called **lamellae**
100
what are **gil filaments covered in**?
**lots of tiny structures** called **lamellae**
101
In what **2 ways** are the **lamellae adapted** to **speed up diffusion**?
**lots of blood capillaries**
**thin surface layer of cells** - minimise diffusion distance
102
how is a **large concentration gradient maintained** between **water** and **blood** in the **Gills**?
**blood flows through lamellae** in **one direction, water flows** in **opposite direction**
103
how is a **large concentration gradient maintained** between **water** and **blood** in the **Gills**?
**blood flows through lamellae** in **one direction, water flows** in **opposite direction**
