Chapter 14 Reproduction In Plants Flashcards
1
Q
Define asexual reproduction:
A
A process resulting in the production of genetically identical offspring from one parent
2
Q
Define sexual reproduction:
A
The process involving the fusion of the nuclei of two gametes to form a zygote and the production of offspring that are genetically different from each other and from the parents
3
Q
Define gamete:
A
A sex cell
A cell with half the normal number of chromosomes, whose nuclear fuses with the nucleus of another gamete during sexual reproduction
4
Q
Define fertilisation:
A
The fusion of the nuclei of two gametes
5
Q
Define Zygote:
A
A cell that is formed by the fusion of 2 gametes
6
Q
Define diploid:
A
Having 2 complete sets of chromosomes
7
Q
Define haploid:
A
Having only a single set of chromosomes
8
Q
Define mitosis:
A
Division of a cell nucleus, resulting into genetically identical nuclei
(i.e. with the same number and kind of chromosomes as the parent nucleus)
9
Q
Define meiosis:
A
Division of a diploid nucleus, resulting in four genetically different haploid nuclei.
(sometimes called a reduction vision)
10
Q
Define sepals:
A
Leaf-like structures that form a ring outside the petals of the flower
11
Q
Define petals:
A
Colored structures that attract insects/birds to a flower
12
Q
Define stamens:
A
Male parts of a flower
13
Q
Define filament:
A
The stalk part of a stamen
14
Q
Define anther:
A
The structure at the top of the stamen, inside which pollen grains are made
15
Q
Define pollen grains:
A
Small structures which contain the male gametes of a flower
16
Q
Define carpel:
A
female part of the flower
17
Q
Define ovary:
A
The part of the flower that holds the ovules
18
Q
Define ovules:
A
Small structures that contain the female gametes
19
Q
Define style:
A
The part of the carpel that connects the stigma to the ovary
20
Q
Define stigma:
A
The part of the flower that receives pollen
21
Q
Define pollination:
A
The transfer of pollen grains from the male part of the plant (anther of stamen) to the female part of the plant (stigma)
22
Q
Define self-pollination:
A
The transfer of pollen grains from the anther of a flower to the stigma of the same flower or a different flower on the same plant
23
Q
Define cross-pollination:
A
The transfer of pollen grains from the anther of a flower to the stigma of a flower on a different plant of the same species
24
Q
Define seed:
A
The structure that develops from an ovule after fertilization, it contains an embryo plant
25
Define **dormant**:
Inactive, with metabolic reactions taking place very slowly/not at all
26
Are there gametes involved in asexual reproduction?
No
27
How do cells divide to produce genetically identical cells?
Through **mitosis**
28
What do you call a primitive organism that makes use of asexual reproduction?
*Hydra*
29
Name the differences between Asexual and Sexual Reproduction:
**Asexual**
1) *1* parent
2) genetically *identical* offspring
3) *no* variation
**Sexual**
1) *2* gametes
2) genetically *different* offspring
3) *increased* variation
30
What are **chromosomes**?
Long threads of DNA found in the nucleus of a cell
Contains a set of instructions = genes
31
Where do tubers form?
On stems that grow on/under ground
32
Give 3 examples of **asexual** reproduction in **fungi**:
1) **fragmentation** → piece of fungus breaks off, could develop into new individual
2) **budding** → unicellular fungi can bud off a new individual (rather like cell division)
3) **spores** → spores are dispersed by the wind then grow into new individuals
33
Give 3 examples of **asexual** reproduction in **plants**:
1) **fragmentation** → if a stem/rhizome connecting parts of a plant is broken/dies, the parts of the plant can develop into new individuals
2) **budding** → a lateral bud n a stem near the soil develop into new plant
3) **bulbs/tubers** → they can develop into new individual plants
4) **artificial cuttings** → cutting of a piece of stem, can be introduced to grow roots
These cuttings can then be planted to grow a new individual
5) **artificial tissue culture** → single plant cells can be grown into an entire plant in the laboratory
34
What is a *Hydra*?
A tiny animal
Lives in fresh water
Related to sea anemones
35
How does a *Hydra* reproduce?
Reproduces asexually by growing buds which develop into young *Hydra* before breaking away from the parent
36
How do animals reproduce **asexually**?
**Budding** → a new individual is budded off from the *column* and then it pulls off to become a new individual
37
Where are gametes made?
In reproductive organs
38
What is the male gamete in a **plant** called?
Pollen
39
What is the female gamete in **plants** called:
Ovule
40
What is the male gamete in **animals** called?
Sperm
41
What is the female gamete in **animals** called?
Ovum
42
Name the characteristics of male and female gametes in **both** animals and plants:
→ Male gametes are **smaller** than female gametes
→ Male gametes are **mobile**
→ Female gametes are **not** mobile
43
What happens during fertilization in plants?
The **nuclei** of the **2 gametes** fuse to from a **zygote**
44
Name 1 characteristic about the chromosomes in a zygote:
A zygote has the same number of chromosomes as the parents
45
Name 1 characteristic about the chromosomes in a zygote:
A zygote has the same number of chromosomes as the parents
46
How is it possible that the **zygote** has the **same** number of chromosomes as the parents?
The gametes are **haploid** (means they have **half** the number of chromosomes of the parent)
So when 2 gametes fuse, 2 haploid nuclei fuse to form a **diploid** nucleus of the **zygote** with the **same** number of chromosomes as the **parent**
47
True/false: A zygote grows and develops into a new individual that is genetically **unique**
**True**, because gametes are only present in **sexual reproduction**
Each individual produced by sexual reproduction has their *own* unique genetic information
48
What does it mean if a flower is a **hermaphrodite**?
They have **both** female and male reproductive organs within a **single flower**
49
What are the 2 things that flowers are either specialized for?
Wind-pollination
Insect-pollination
50
What are the characteristics of a flower that is specialized for **insect**-pollination?
→ bright, colored petals
→ nectar
→ smaller amounts of round, sticky pollen
51
What are the characteristics of a flower that is specialized for **wind**-pollination?
→ less bright petal
→ **anthers** that hang from flower
→ larger amounts of smooth light pollen
52
What type of flower is particularly specialized for wind-pollination?
Grass flowers
53
Name 3 general structures of a flower:
→ sepals
→ receptacle
→ pedicel
54
What is the function of the sepals?
To protect the flower when in bud
55
Define **receptacle**:
Area where flower structures **attach** to expanded end of flower stalk
56
What is the **pedicel**?
The flower stalk
57
Name the male reproductive organ and what it consists of:
**Stamen**
→ filament
→ anther
58
How many pollen sacs does the anther have?
4
59
What is the function of the filament?
It holds the anther in position so that it is accessible to birds, insects and the wind for pollination
60
Name the female reproductive organ and what it consists of:
**Carpel**
→ stigma
→ style
→ ovary
→ ovule
61
How does the structure of the stigma enable its function?
The stigma is a **sticky surface** so *pollen grains* can easily **attach** to it during pollination
62
What happens to the ovary after fertilization?
Developes into **fruit**
63
What happens to the ovule after fertilization?
It developed into **seed**
64
What happens during pollination in a flower?
Pollen grains are transferred from the **anther** to the **stigma**
65
What happens when the flower buds open?
The anthers split open so the pollen is made on the outside of the anther
66
What is the structure of a pollen grain and how does this affect it?
Pollen grains are surrounded by a hard coat so that it can survive in difficult conditions
The coat → protects the male gametes inside of the pollen grains as its carried around from one flower to another
67
Why is a self-pollinated plant more likely to decline in species if the environment changes rather than a cross-pollinated plant?
The self-pollinated plant will have **less variation in its offspring** than a cross pollinated plant
So does **less able** to **respond to changes** in the environment, **overtime**
68
What is an advantage that self-pollinated plants have that cross-pollinated plants do not?
A self-pollinated plant is **not reliant on pollinators** in the same way as a cross pollinated plant is
69
Why will a cross pollinated plant have more variation in its offspring then a self-pollinated plant?
Cross pollinated plant has a greater genetic variety of the parents which enables it to have more variation in its offspring
70
What 4 things should you look out for in an insect-pollinated flower?
→ large, colorful, and sometimes scented **petals**
→ **nectaries** producing nectar
→ **stamen inside the flowers** so the anther, will touch the insect
→ **stigma inside the flower**, so the pollen will brush off the insect and stick to the stigma

71
What 4 things should you look out for in a wind-pollinated flower:
→ **no** petals/very small petals, w.o. bright colours
→ **no** nectaries
→ **long** *filament* so that the *anther* hangs **outside** the flower and pollen can be blown away by the wind
→ **large feathering** *stigma* **outside** the flower to catch pollen blown in the wind
72
Make a flow diagram to show how pollen travels:
Anther → stigma → style → ovary → ovule
73
What are 3 differences between wind- and insect-pollinated **pollen**?
**wind**
1) smaller amount
2) round
3) sticky and/spikey
**insect**
1) larger amount
2) flattened
3) smooth
74
What happens after a flower is pollinated?
The **male gamete** found in pollen grain **→** grows down **style** **→** toward **ovule** **→** in ovule nuclei of male and female gamete fuse during **fertilisation** → **zygote** is formed → zygote decides by **mitosis** → forms an embryo in seed (ovule) → eventually **germinates**
75
How does the male gamete inside of the pollen grain reach the ovule?
Pollen grain grows a pollen tube (microscopically small tube) down the style of the flower
It then grows through the ovary wall → enters through the micropyle into the ovule
76
Define **micropyle**:
A tiny hole in the ovule
77
What happens during germination?
The **testa** (seed coat) cracks open → the **radicle** (1st root) emerges from the seed → where after the **plumule** (1st leaves) emerges
78
What are the nutrients stored in seed used for?
Early **growth** and **development**
79
When does the new plant begin to photosynthesise?
When the first leaves are exposed to sunlight
80
How can a seed survive harsh conditions before it begins to germinate in the right conditions?
When a seed forms → water in it is drawn out → seed is dehydrated → no metabolic reactions can take place → **dormant** → can survive harsh conditions
81
What are 3 important conditions that affect the germination of seeds?
1) Temperature
2) Water
3) Oxygen
82
Why is temperature an important condition affecting the germination of seeds?
→ Temperature affects enzyme activity
→ Reactions in germinating seeds → controlled by enzymes → therefore temperature dependent.
→ germination tends to happen between 20°C and 30°C
83
Why is water an important condition affecting the germination of seeds?
Water is needed for:
→ the **chemical reactions** in the germinating seed and growing seedling
→ **metabolic changes** (such as digestion of *starch to sugars* and *proteins to amino acids*)
→ **cell growth** in the growing seedling
→ **photosynthesis** and **transport** as this evening grows
84
Why is oxygen an important condition that affects the germination of seeds?
→ growth processes → require large amounts of energy → large amount of oxygen used to produce enough ATP → during aerobic respiration
85
Compare insect-pollinated and wind-pollinated flowers:
